might be a superficial take, but the other site looks better than yours, which might make people like it, want to visit it, and trusting it more than yours, which could signal to google that your competitor's site is better (google relies heavily on user feedback and engagement when ranking sites)
Another thing that I'm seeing at a first glance is that your competitor has a physical address and phone number associated with it while yours doesn't, which makes that site totally legit and transparent in google's eyes, something that google loves to see.
These are just 2 things that I could easily spot as a neutral viewer and if your competitor's site impressed me more than yours it's safe to assume that other neutral viewers will probably feel like me too, which - once again - will send signals to google that the other site is better, therefore it deserves to rank higher
Oh, and I'm also not seeing any Cookies page on your site, whereas on your competitor's site there is one, and you know that GDPR is a big thing here in Europe, so you probably want to make that page, too. I don't know if this page is exactly the reason you've got outranked, but if the top ranking site in your niche has it you'd better have it too, just to be extra safe.
I don't have access to SEO tools to check the sites, but you said that you do have access to them, so plop them both into all of those tools and compare the backlinking profiles of both sites, the content amount, quality and optimization of both sites, the number of indexed pages and ranked keywords of both sites, the social media presence of both sites, and whether or not the other site is doing Google Ads (sometimes, sites that pay for Google Ads get rewarded with better rankings and traffic, like it or not)
Check all of these things for both sites to see where you lack behind your competitor and fix accordingly!
