if CTR is all you want you can look into CTR manipulation, but you gotta be careful about it as this can backfire if you're doing it wrong. Unfortunately, I've never done CTR manipulation so I wouldn't know what to recommend, but luckily, this thread just got created today and you could get some tips from it
https://www.blackhatworld.com/seo/is-ctr-effective.1727528/
But to be honest, the CTR is probably less important than other stuff, like your average position, for example. 26,5 is too low of a position, so try to improve that first, and with higher rankings you might get more traffic, and the low CTR might not even matter at that point...
Just select the highest and lowest ranked pages (both in terms of clicks, impressions, and average position), and see what you can do about improving them. Like for example...
1) the pages with most clicks might need more impressions, therefore you could find more related keywords that those pages don't have, and naturally work those keywords into the content of those pages to attract more impressions and even more clicks.
Or, it's possible that the clicks and impressions are at their possible maximum, but their average position is low (which is very possible given your site's low avg. position) in which case you can try boosting their position in the SERPs by - first - pointing a few internal links with exact / partial match anchors to them, from other relevant pages that are indexed and get a lot of traffic and then - if the internal links don't improve the rankings within 1 week - point a few quality links (guest posts preferably, don't do PBNs to internal pages, it's not looking great IMO, but you can also try some tiered link building with web 2.0s as 1st tier and then blast the crap out of those web 2.0s with whichever backlinks you want, even garbage ones)
2) the pages with the least clicks will almost definitely need CTR improvement, in which case you can test CTR manipulation software for those pages (if that's feasible, because I think CTR manipulation works best with branded search only, at least that's what I've heard but I could be wrong, but you can test this on 1-2 pages that are so bad and that you have no hope for recovering that it's worth trying CTR manipulation on them). Or, if you don't want to risk using CTR software, you can change their meta tags (I would still change / add a few sentences here and there, though, just to give the content a boost of freshness, maybe this will trigger some positive thing in the retarded google algo)
3) the pages with most impressions will probably - again - have poor avg. position since your site's overall avg. position is bad to begin with. So, for such pages again try the internal links trick first, and then the normal backlinks trick secondly...
If the avg. position is OK (as it's deemed by you, some people really are happy with top 10 rankings, for example, and they couldn't care less if they rank #1 or #8, and this might be your case too)... So, if the avg position is good for the pages with the most impressions and you're happy with this situation, it's possible that the clicks are low, in which case you can try again the CTR manipulation and / or changing the meta tags and / or changing / improving the content.
If none of these tricks increase the clicks within 1 week after you make these changes and the googlebot revisit those pages you could try the internal links trick again. Internal linking is a very powerful tool nowadays, that can do wonders in certain cases, just don't overdo it. I would say get 2-4 internal links from other relevant pages, but use exact / partial match anchors just for extra punch.
4) the pages with the least impressions obviously need more impressions, which is basically the same situation mentioned at point 1. So, follow that advice
5) the pages with the lowest avg. position could always go higher. And you can achieve this with more and better backlinks and authority. More authority means you need to build more links to the homepage of your site mostly (like, 6-8 out of every 10 backlinks that you get you can point directly to the homepage), and the remaining 2-4 backlinks you can split between the inner pages that could use improvement on their avg. positions, and other important pages on your site (category pages, for example, if you're doing ecommerce)...
6) the pages with the highest avg. position could need improvement if the highest position is not in top 3, for example. Or, if you're already ranking #1 then you could try to improve the CTR of those pages, but to be honest I would not test CTR manipulation (if you've never done it before) on pages that already rank #1.
So, the pages ranking #1 (or top 3, or top 5 if you're happy with those positions) I would not touch with software in this initial stage.
Something else that you could try is find all of the queries that google ranks you for (regardless of which position they rank you for, but I would start with those that rank you in top 10 as they seem the easiest to do something with) but you have no page that targets those queries. I would take those queries and group them in topical clusters and then create 1 page for each topical cluster.
But you need to respect the intent of those queries, if they're info keywords set up a blog and create info content around them, if they're physical products do product pages, of course. If they're other type of intent (images, local services, etc) create relevant pages (image gallery page, Services page, etc) of course...
In conclusion, I don't think that the CTR is your biggest problem. Sure, 4% is not a lot and it can definitely be improved, but your site's avg. position is worse than the CTR in my opinion, so I'd work on that first.
Also, I don't intend to disappoint you, but SEO is dead in my opinion, and it's possible that even if you improve / fix some / all of the issues your site might still tank tomorrow or next month when google roll out another update meant to steal more from the people and claim as their own like their AI is doing. So, try to diversify your traffic sources as much as you can. Easier said than done, I know, but you gotta start somewhere... Or, do like me and don't play the SEO game ever again until google falls completely and other search engines take their marketshare (which could mean years or decades at this pace)....
Anyway, I've got no more solutions to offer if the ones above don't work, as I've been out of the SEO game for nearly 4 years now, and I'm not very sharp and up-to-date anymore with all of the things that are going on with this imbecile company that never gets held accountable for any evil that they do. Nowadays, ranking in google is more technical than ever with all of that retarded structured data and AI and whatnot. It's way above my level of understanding and willingness to adapt to google's ever moving goalposts, so yeah.... I don't know what else I can do to help you, sorry!
Either try some / all of the suggestions I gave, or maybe another kind soul will chime in with better tips. Regardless, good luck!
