Limited options of what I can buy. The only TVs here for affordables prices are ones with Android 9 or 10. If it's between 9 or 10, is it worth it to pay a little more for 10 or are 9 and 10 pretty much the same with 10 only having design and useless features for example. What do you suggest? Or should I pay a lot more for a tv with 11?
Android TV version would be the last thing I'd look at when purchasing a TV. Having the OS built it is nice to have, even if it's slower than a separate box but OS version is pretty much irrelevant. I have the Shield and couldn't care less about updates.
There is little to no difference in Android 9 and 10 for you or in the back end. But Android 10 uses a lot more resources and takes up lot more space compared to 9 while offering nothing in return. I have Android 9 TV from Infinix which I got in 2020, It got an 900 mb update just two days ago updating internal apps and play services. Most of the important components of the OS have already been moved to Play Services and are updated standalone.
In short, there is no benefit, look at other features while making decision.
I would never buy a TV based on the OS it runs. Buy a tv based on the features and quality of the display. Then get a device running the OS you want that will actually get updated and perform better than the poor performance of most tvs.