How to choose the best admin panel for an online store?

Question

Search Engine Optimization

Good afternoon. There is a need to create an online store, but in what vein - site.ru - one admin panel lives here, on it all the information, landing (inside the site or on a subdomain), according to site.ru/shop (or send it to a subdomain?) hangs online store script. There are not many goods, so the main task is the operation of the basket and the IM functionality, the rest can be done manually without automation.
1. The site itself will have information traffic, articles + landing pages. In Ave or Modx, the functionality is enough for this.
2. On /shop there will be a pure online store script. For now, the task is to establish sales (callbacks, shopping cart, order functions, product output, categories - subcategories, etc.), I will think about automation and the user's personal account, and about all the other bells and whistles after. The template will be one for both sites so that the user does not see the difference.
Actually, the question is this. Maybe I'll reinvent this wheel in vain (I'm planning some kind of wordpress / modx / ave in conjunction with presta / opencart) and is there something that already knows pages inf + script IM? I didn’t deal with landing close in terms of promotion and work with them, because. there were no orders for them, only typesetting and so on the little things, how best to organize them - is a separate domain or subdomain enough? Or will it fit in the site structure at all? Let's say part of the traffic goes as it goes - to categories, the other part goes to landing pages (from which the margin is tastier or the season or% reason_name%). How would you do? Thank you.