Best phone sync

Edit: Thanks for all the suggestions. I'm going to try sticking with syncthing and try the fork of the UI and see if that keeps everything working.

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I want to sync files between my linux PC and Android phones (mostly for Obsidian notes).

Can anyone recommend a good real-time sync?

I've been trying syncthing, but despite turning off battery optimization for the app, it rarely sees the phone as connected. I don't want to have to remember to check syncthing every time I edit a note.

I use resilio for syncing between PCs but it looks like it has a high battery usage on the phone, as if it is frequently polling for changes.

I use FolderSync for occasional scheduled syncs (e.g. updating my MP3s from the server to my phone), but a scheduled sync either is frequent enough to affect battery or it risks sync conflicts.

Cloud services such as OneDrive, Dropbox and Google Drive don't show up as big battery drains, so I assume that they use change notifications from the OS instead.

Are there any real-time 2-way sync apps for phone that don't have big battery drain and are not for cloud providers?