Since you are considered about security, I recommend setting up a VPN (some routers support it, or you can run it on a SBC or old machine). It's a bit of a lear

Since you are considered about security, I recommend setting up a VPN (some routers support it, or you can run it on a SBC or old machine). It's a bit of a learning curve but it's a clean and secure solution in that the VPN provides the main line of defense - vs. securing individual endpoints if you expose their ports to the public internet. The VPN will let you RDP or SSH/VNC into their machines for remote manitenance. Since it gives you access to their entire LAN, this has the bonus of you being able to access and configure other devices like security cameras/etc. If security is less of a priority there are simpler options other commenters have discussed like Chrome RD, Teamviewer, etc.