Thanks for sharing your experience. As you pointed out and tested that using really short cables or a powered USB hub eliminates your unstable connection problem means that lack of power could be the root cause. Anyway, I came across a good article that I bookmarked for future reference in case I also run into the same external monitor problem. Hope it helps, and thanks for sharing!
17 Ways To Fix External Monitors Not Working On Mac (inc. M1/M2 Macs, Ventura & Monterey)