I think I've accomplished all I can for now with this VM. My new laptop will be here in a couple days, and I'll load Solus 4.5 Xfce on it to see whether any of the flaws I found with the VM are not present on hardware. For now, I'm going to devote some time working with the other 4.5 version DEs. I suspect there will be much less for me to do with those, as they're time-tested Solace editions instead of one that's completely new.
So, after configuring this VM to match my daily-driver laptop, I've been using it as a replacement for that laptop for several days now. I've read and answered emails. connected with my bank and paid the small balance on my VISA card, on Schwab I've reviewed my investments, I've connected to my clinic's portal (MyChart) to review my latest test results, ordered a grocery delivery from my nearby supermarket, watched TV on tv.google.com, chatted with a friend in Arizona using Telegram, played all three solitaire games, had lunch delivered by DoorDash, and much more that I've probably forgotten by now.
The point is that as this Xfce machine is configured, I could very easily use it for everything I need a laptop for. And after the first bugs that I documented, my relationship with Xfce has been very cordial. No, @Brent, I'm not ready to give up Plasma for Xfce, but I could, without much suffering at all. So until my laptop gets here and I install Xfce on it, this will probably be my last post on the subject.
I have one final request for the team: please consider creating the next .ISO file with a top panel and the plank, as I've used it here. It's been a pleasure to use for all these days. And maybe a background like the one I selected (see earlier picture) instead of the one that makes it look like Solus' GNOME edition. I think it would make a much better first impression.