If you're thinking about self-hosting anything, my first recommendation is to get your backups in order now, before doing anything else. I wrote this a while back: <https://photostructure.com/faq/how-do-i-safely-store-files/>. Having a full, offline backup will only cost ~$20/TiB nowadays, which is cheap insurance if whatever app you try out doesn't quite behave as you expected it to.
The second step is to make sure your server is both hardened (<https://forum.photostructure.com/t/server-hardening-for-begi...>), and ideally, only available via a VPN (like TailScale) or at least via a reverse proxy (Cloudflare has a free solution). I compared and contrasted some of these solutions (along with instructions) here: <https://photostructure.com/faq/remote-access/#accessing-your...>
The situation for self-hosting your photos just a couple years ago was pretty bleak--especially if you had hundreds of thousands (or more!) of photos. That may sound like a lot of photos, but for people shooting digital for 20+ years, it really isn't!
Whatever image manager you pick, make sure the app follows existing metadata storage standards, so in the (seemingly inevitable) future when the app is abandoned, your photos are in directory structures that make sense to you, and the work you've put into organizing them isn't locked up in unreadable databases or folder structures.
Spoiler alert: I got burned by this issue with prior apps, so I designed PhotoStructure from the ground up with exactly this in mind: <https://photostructure.com/faq/why-photostructure/#open-stan...>. Unfortunately, many/most self-hosted solutions don't handle multiple source directories and configurable destination directories.