I will recommend xpra, it’s seamless mode is fantastic for running individual programs. Lots of other features that I haven’t tested yet as well, like the Windows client. Shadow mode lets you attach to an existing session. There is also a full desktop mode that should work more similarly to VNC, but I haven’t gotten it to work for me sadly.
I also use Sunshine together with Moonlight to get a bit more responsive results for remote gaming.
Haven’t looked into Wayland support in terms of the remote for either, but both solutions work on my laptop with Plasma 5 Wayland session.
EDIT: Forgot to mention that I use a VPN for actually accessing the remote host on the go, but on a LAN you don’t need anything special.
+1 for Sidebery. It took me some time to get used to it, but now I can’t go back.