I'm not up to date on the current market, but I have Ikea blinds that are battery operated which I control from HA. The batteries are rechargeable, and the batteries themselves have micro-USB ports for charging.

One option would be to buy these, see what kind of charging port they come with these days, and try to make some physical modifications to jam a USB connector in there. From there, you just have to figure out the solar part. A lot of solar charge controllers have USB ports which should work to charge the battery, but they are clunky and you'd have to mount it on the wall probably.

For what it's worth, the batteries in these shades last quite a long time... Looking at one of them, I last charged it in September 2024, and it's still at 72%. It goes up/down at least once a day I'd say.