Easy way to folder sync from phone to server?

Hi all! I’ve recently migrated from Core to Scale and I’m currently redoing the plugins I had there. One of the ones I’m having trouble with is syncing a backup of my photos folder to the server. I previously used Nextcloud which worked very well. The issue I’m facing is having the data visible in my shares. I can’t remember how I got it to work in Core but I know it was a bit difficult. I feel like it should be possible given I’ve got QBittorrent working pretty much as before and everything through there is easily accessible.

The two main reasons for this is that I’d like to use something like Photoprism going forward and also having my photos directly accessible via the explorer has been very useful to send images from my phone in emails for example when working at my desktop. I’m not wedded to Nextcloud if there’s a better solution but I did have it working well before. I tried Syncthing both when I was having trouble on Core as well as now but the web UI says the phone is disconnected and I can’t find any way to force it to reconnect on either end.

Any ideas on things to try?