(Mods, let me know if there's a better place for this)

I'm interested in posting more explicit content here, but I'm slightly dubious about the need to upload government ID. I don't really want to give a copy of my passport to a stranger.

Anyone had issues, got tips?

The reason for the requirement to verify to post explicit content is so as to prevent anonymous users from uploading content they have no rights to, whether that be pirate, non-consenting models, under age models, revenge porn, etc. Basically to be able to publish explicit content the publisher is expected to be identified and take responsibility for what they've uploaded. This rule for adult content upload was brought in by the card associations in response to well documented abuse cases on large and well known tube sites, so it's permanent and not going away.

As to trust, personally I'd trust MM with my personal data far further than a large corporate site, only he gets to see the data and he stores it off-line, not in the UMD back-end, so it's hack-proof.

And while there's nothing technical to prevent someone using a fake ID or someone else's ID to verify an account, if they do that then they're potentially comitting a serious criminal offence with very major consequences, which is generally enough to ensure people stay honest.

This is a New York Times article which touches on why the new rules came in:
https://www.nytimes.com/2020/12/10/business/visa-mastercard-block-pornhub.html