How well does Nextcloud work with fediverse? - eviltoast

I am interested in possibly self hosting a Nextcloud instance. Couple of questions, if I self host a lemmy or pixelfed instance can it source photos or videos from my theoretical Nextcloud instance?

Another question is can I have it only sync while on the WiFi at home instead of over cell? Any way to enable access via wire guard while out and about but then only synch when at home?