Uploading VeraCrypt file via browser

I haven’t had issues using VeraCrypt + Proton Drive and don’t see why there’d be an issue in the future. I agree with @SYST3M_D3STR0YER that Picocrypt-NG could be another good option since it’s a simpler program, but it’s not yet recommended by PrivacyGuides because the new developer(s) have to build its reputation from scratch.