Relationship sharing money question 🆘

My partner decided (and we agreed) that he wants to put me in charge of all his money because he realized he is extremely irresponsible with his money and it’s caused tons of issues.

We have separate bank accounts right now (different banks) but I’d be joining his bank...

My question is it better to get a joint account (while keeping our separate accounts) or for me to join the account he has now?

We decided I’ll keep my own account either way.

Any other advice would be so much appreciated

*we are not married yet if that matters but we’re planning on it in a few years