Sounds like you need an accountant.
Accounting is important, but it's not the solution to the OP's problem. There are also questions of costs and efficiency, especially since we are talking about low-margin B2C sales.
MoR are great if you want absolutely no liability whatsoever, but especially considering there is no way for other countries to check you’re paying the right amount, I think doing it yourself isn’t too risky. (Not doing it is also a possibility.)
It's also unlikely that a single accountant will be comfortable filing taxes in all of the jurisdictions (or maybe I will be pleasantly surprised).
You shouldn't need to hire a high-priced professional just to sell a thing on the internet. That kind of friction just makes everyone poorer.