I disagree that you need a lot of space for self hosting. Unless you want to host streaming content for thousands of users, Intel NUC or raspberry PI on top of your router is plenty enough to host nextcloud, some webservers with decent traffic (assuming you have gigabit connection, which is now commonplace), email, backups and media server for family and friends.

Wouldn't it be rather awkward to set up a redundant RAID array on one of those though? Which is something you definitely want on a server that stores backups. I know you can obviously connect as many hard drives as you want to a Raspberry Pi via USB, but that feels wrong for a server. Intel Nuc at least has Thunderbolt and probably some internal SATA ports.