...zoom or another meeting system would require the other side to accept the connection. Using...what? OTOH, low-level remote access usually lacks any UI (such as the mentioned KDE Connect's Remote input, which mimics another input device).
But again, this requires some planning beforehand. Even "ssh in, install a remote viewer and use that" would require SSH to be there and reachable from outside (as NAT is likely). In the end, this is no different from "just grab the wired mouse and plug it in. Which one? Well the one you prepared beforehand."