I use Privacy.com to get temporary credit cards, to avoid the hassle of compromised credit card numbers, although it doesn't stop various governments from tracking my transactions.

I've bought RISC-V SBCs from both Pine64.com and Arace.tech, and neither required I make an account. Arace.tech does require JavaScript to checkout, but Pine64.com does appear to work without it, although I didn't complete a transaction without it. Pine64.com also accepts USDC payments, but no other cryptocurrency.