The battery turning into a Spicy pillow is always a Concern for using laptop as an always powered on server. So even though you will be away from it, make sure that there is a way for someone to keep an eye on it, once every week or two.

That said, I have been using a dell laptop as a desk workstation (and remote use) with an uptime of 2.5 years at this point.

I also use syncthing. And it works pretty well. There is some turmoil with the android version in light of changes so the underlying sdk. And I am not sure there is an iOS syncthing that would work as well. I actually use it primarily to sync my keepass databases, and before Immich, my photos.

The photo management Immich brings makes it a nice alternative for that use case, but either way I need to have one or more servers elsewhere managing storage so I can get things off of my phone into a system I can control.

I use Immich because I have multiple devices and multiple people uploading photos to it , so we can all organize together.

Self hosting anything also gives you a lot of practice and experience (and confidence) to also self hosting anything for others, an important skill for many to have in order to have a more distributed internet.