I've had some luck with Anydesk. I used to use Teamviewer on my project PC's but it kept getting flagged as commercial use and I'd have to e-mail them every other month to get my account unflagged. I for my headless/VMs did have some promise with SPICE[^]. If I'm stuck with VNC, I usually used TightVNC. I've found VNC slow with higher resolutions and color depths.

I love this post. It's so universal!