Nah, I’m good.

2 main issues with it:

Too slow for the average user. A lot less torrents available.

I self host using mailcow. Easy setup. Prevents most of the beginner pitfalls via exemplary documentation.

With nextcloud you can create shared folders. You can give him access to the shared folder via his own account. Anything put inside the shared folder is available to you both. He won’t be able to access the rest of your stuff.

Unless he has admin access to the server itself. But you can also enable encryption.