Well... It seems it's not as simple as I had hoped. Yesterday morning I turned my computer on and there was a Avast popup on the screen which clearly said "Avast Antivirus Free" on the upper left side of it, and that a program update was available. I scrutinized that popup and there was no mention of Avast One, until I clicked on Update. Then a smaller, lower right corner popup said something to the effect of "Updating to Avast One Essentials." Now in my opinion that was not an offer, and I hate to call it "deceptive" as that seems rather harsh, but I will say it definitely lacked pertinent information indicating specifically what the update was for. And it did not seem to have an option to decline the update. At least not one I could see with low vision. (Which does not mean there wasn't one...)
So I repeated what I did the other day and reinstalled "Avast Antivirus Free" and set it nearly the way I had it before all this happened, but I set it to automatically update both the program and AV definitions. This morning, I was not tricked again. So I hope it stays that way, because while "Avast One Essentials" seems to work essentially the same as the other version, but that bright skin is a real game changer for me. (And this forum is even worse far too bright for me, so I wrote this offline.) If I can't keep the one I prefer, I may have to change AV software, which I would rather not do. I've had Avast in my last three computers, this one I bought in 2016, the one before that in 2013, and before that in 2010 and never had a single virus.