Honestly, your best bet will always be an Apple TV because of how the ecosystems work. Developers build apps for Apple and Android. Apple device code is fairly uniform across all OS platforms (iOS, iPadOS, tvOS) and so your chances of stability are highest there.
Android apps are also high priority, but because of how Android is fragmented, you'll always have a bit less luck there. Android TV and Fire TV are pretty much forks off main Android and are usually a few versions behind the latest Android LTS for phones. This leads to some feature breakage and reliability problems. LIke anything YMMV and some people experience zero problems, while others just have a terrible experience.
These days, I think Roku increasingly falls in between Apple and Android. Developers are really starting to target that for their apps and I welcome that. Most people are very happy with the Roku ecosystem, so if you're not an Apple guy, you probably should go with that.
Personally, I had a lot of FireTV devices but the reliability started declining and the ads started increasing. I think I only have one Fire Stick left now and it's in a room I barely watch TV in.