Just a comment on something that I find works quite well. I've been taking formal piano lessons from an excellent teacher for about ten years now. (For those who know or might care, I'm working on Mozart's Sonata in C Major which he called "An easy, simple piece for beginners" (my translation) and Chopin's posthumous Waltz in A Minor. I'm no prodigy.) During the Covid lockdown we went to FaceTime and that worked well enough that we occasionally resort to FaceTime now when an in-person lesson is impossible or inconvenient. I'm not a fan of trying to learn classical piano from YouTube videos but D/L with an actual teacher does work. I've never tried a group lesson by Zoom. It might work but the time delay would mess up duets or trios.
My choir used Jamulus during the pandemic, and it did a surprisingly good job keeping everyone together, and that was like twenty people in twenty different places. https://jamulus.io/
This is a timely thread. I have been considering taking guitar lessons from a teacher based in the UK. I've followed his YouTube channel for years, and am ready to begin. One of the things holding me back was that I wondered how effective DL could be in this educational lane. Also the time difference (6 hours ahead) gave me pause, but not anymore as I'm pretty flexible. Glad to hear of your good experience Norm, so I can now make the leap from an intermediate guitarist (stuck in a rut) to become the next Clapton. Ha!