Yeah, for me I primarily use Syncthing just for syncing between servers and computer.
I switched to Migadu for my primary email which includes CalDav and CardDav. I also run Hydroxide in my K8s cluster for Protonmail syncing on Apple Mail -- I could also switch to that for CalDav and CardDav if I wanted to.
There isn't much I actually need Syncthing for on my phone nowadays. Even if I was back on Android I can't think of much I would need it for -- for my workflows.
> Nextcloud is what I ended up using
Nextcloud has always been one of those projects I appreciate so much but find so bloatey for me as a single user and always end up getting rid of shortly after I install it. I feel like if I had a team of users (work, friends or family) who fully committed to using it then I would love it.
Btw, none of this is meant as a criticism to your setup -- it sounds perfect!