No worries man. I can think of 3 different things that MIGHT work, besides looking on ebay
for something old school. I also go to PnP. I would bet the 80s-90s pickups are your best chance. (not sure when you go out, but I know mine puts my vehicle out on Tuesdays. If you aren't there within an hour of it being lifted out into the yard, the good stuff the resellers can make money off of is gone, (those clowns never know how to pull parts off either, and end up breaking most things). I'll try not to rant in your thread
1. You can still find an old school radio (60s and 70s cars), but you are going to pay $200-$300 for em.
There are quite a few sites, but something like this would have options:
2. You might want to try https://www.crutchfield.com/
(the site is not working for me at the moment).
Many of the newer head units come with a remote control, (did you double check in the glove box, back of the seats, center console, door cards, just in case yours has one). Some remotes are dinky and you would need child sized hands to use, BUT, SOME are designed for clunky use and in ways that you don't have to look at em. I have seen some that look like upside down hand sized cones. They would have a top and bottom and you twist them for different functions. I THINK you can sort head units by the ones that have remotes and if you search through their user manuals, you can search, and might find something that will be really easy to use.
3. There are universal steering wheel controls. They connect to your head unit, (usually by bluetooth), and have big easy buttons on a control that you mount to your steering wheel, right where you keep your hands. There are different styles, but here is one that should give you an idea.
Also, you didn't say the kind of vehicle. Maybe swapping in something with steering wheel controls is an option.
I also have two Kenwood head units. To adjust anything, you push on the big round volume button to get into the menu, then turn to go through the list, and push again to change anything. It's pretty simple, and I can't think of any new head unit that isn't going to have a bunch of features. You might be better off with one that just has em, but has controls that are a little easier to use. Not sure of your style, but no reason you can't go into a best buy, or stereo store, and mess around with different brands and see which one has functions that are easier to use. Best Buy you're more likely to not be hovered over by a salesman if you tell em you are good one time, and they always have a nice display set up so you can try all sorts of different head units and speakers.