Though Bitcoin was created as alternative which I think make mass adoption somehow impossible/hard to achieve but there is always a solution to very problem.

This issue of been discussed several time but i can assure you if all governments around the world supported digital currency a solution will be created, we have good thinking experienced Dev within the system.

The last time i checked the TX fee of cryptocurrency is not higher than payment services if you know how to do it professionally and if private keys are not friendly to you, you can make use of the custodial wallet but the fee is ridiculous sometimes.