Random cheap boxes aren't worth it in my opinion, they are buggy and usually drop support quickly - meaning you'll have to buy a new box sooner to keep supported versions of apps. Meanwhile I have a Mibox 3 (2016) and an Nvidia Shield (2015) and they are both great. Mibox 3 got updated all the way to android 10 and Shield is on Android 11 now and still better than most boxes despite being 7 years old.
If I were going to buy a new box today it would be Chromecast gen4 with Googletv. That's google's official box so it should have support for a long time and be the least buggy because the OS is being designed for it.
That 64 GB is storage built into the box, non-removable. I wouldn't recommend the box though for all the reasons I mentioned above.