a.) accounting for the VAT owned to dozens different countries and
b.) "remitting": actually paying the VAT to the tax agencies of dozens different countries
many services help with part a.), but i haven't found a single one that helps with part b.) - you can only circumvent the issue by selling on a platform (like the different app stores or "FastSpring" or awful awful "Paddle") that do it for you because they are the merchant-of-record
our solution is to defer all payments for countries that collect VAT (EU plus UK plus like a dozen evil ones [1]) to FastSpring (which collects AND remits VAT), while selling to countries that don't collect VAT via Stripe.
this works well if you are a small company and you fall below the "VAT thresholds" in place by most countries, but if you are big and breach most thresholds this solution is less effective.
[1] AE, AL, AO, BH, BY, CH, CL, CO, CR, DZ, EC, GE, IN, KE, KR, MD, MX, RS, RU, SA, TJ, UG, VN