Does your hosting provider support scaling that up?
This is all relatively lightweight stuff and I would guess that it could run all at the same time with the exception of matrix which is somewhat heavy.
I would also advise you to not run all of that on the same machine especially if you run some more critical stuff like nextcloud and especially vaultwarden on there. You want that to work and you want that to run reliably and safely. You don't really want a bug in the lemmy instance to take down your private cloud or worse someone gaining access to your vaultwarden databse.