SEO and backliking : Domain and ads strategy

Good day all BHW members.

Can't explain better in the title, here is the story :

I manage an e-commerce website since 2014, I got a good ammount of traffic with Google/Bing/others

I only used SEO to grow my organic traffic, no social media, no ads.
For curious members, I'm able to make 5 figures a month without ads or anything else than SEO.

Years ago, I started a blog in the form domain.com/articles, on the same server.

I made more than 1k articles, and it helped me well to rank in first page for years.

Untill 2017, I was almost alone in this niche.

Now, there is dozen of other ecom stores that sells almost identical products.
None has a blog like mine, but most of them have more time than me to optimize keywords and take over the first page.

I started another blog, same niche, and started building backlink from this new blog to my ecom store and vice versa.
OFC I don't copy/paste previous article, this new blog has new content.

The blog is starting to rank well in Google since I started doing SEO, almost all articles are SEO optimized now and contain a product link from my ecom store, or a freebie to download.

In my ecom store, I started putting related links on product page to my blog (How to use this product, how to install the product etc).

I started with Google Adsense in November on the blog site, before that the blog wasn't monetized as I wanted to redirect potential customers to my store with a banner ad (didn't work well, not enough traffic)

Since then it's not a big thing, but not bad for beer money. 70,00€ from november to march.

I got a big spike in revenue with mailing (I got about 15k customers emails), but spikes are for 1-2 days where I can ear at most 8€.

I definitely need to learn about Adsense, because I can't even set up the GDPR message right now, so I guess my revenue are really limited because ads surely aren't showing to a lot of people as I don't compy with GDPR yet.

Now the question :

Is it better for my strategy to keep only the domain of my ecom store (domain.com, and blog.domain.com) or is it better to buy/use another domain (I have aged one, related to the first domain)?

I'm sure I'm not doing everything right and some of you will tell me, don't go to harsh on me x)

Any tips will be appreciated, I think I will start a journey post when I'll be confident enough to make a real plan for future articles and SEO optimization.

See you guys on this thread, or another!

For GDPR and Adsense, prioritize compliance to maximize revenue potential. Diversify traffic sources beyond SEO by exploring social media and PPC, and utilize your email list more consistently to stabilize revenue spikes.