Those things really need some attention!
Let's hope they get it fixed as soon as possible !
On x5ii, we would actually make our own lightweight themes or fw versions that would be considerably faster than the default. Similar could be done for x3ii, and those two things were major parts of why the daps were so loved, at least for those of us who actually made the custom fw.
I remember spending a week or so porting the x5ii UI to fist x5
Really wish this could be done for x1ii, because I would do it just for the kicks
I have no idea why most daps regardless of company making them at this moment have this slow mSD reading speed and at this point I'm too afraid to ask...
Anyways, a slow or laggy UI should be fixed. I have a few pieces of advice but many of you might not like the result much. The laggy UI is generally caused by heavy graphics. To make it lighter we generally used simple, simple simple components and this made it lighter. It was acceptable image wise. Also PNG compression might play a role, they need to decompress all PNG Components for it to not need on the spot PNG decompression because this is very heavy even on an i7 6700k CPU. Even a small factor of PNG compression can result in devastating slow downs in a mobile device.
I might have many other advice but I'm a Python programmer not pure Android and what the tricks I know are pretty general orentied.
Another advice is disabling the laggy features entirely while not in usage. Android loads the entire OS in ram and this causes it to b quite laggy if it has too many modules and components loaded up. This can be achieved by adding an option for something like entirely disable Bluetooth or other features that might be sacrificed for UI speed. Of course, this might be speculation and this might not work on Android, I am another type of programer , not Android OS programmer so there might be some aspects that I'm not the best to ask about .