App doesn't open when tapping media player
This is a Xiaomi/Miui-specific issue. If you tap on Niagara Launcher's media widget and the player app (e.g., Spotify) doesn't open, make sure your music app has the Display pop-up window while running in the background permission. You can change that by long pressing your music app in Niagara Launcher, tapping on App info, then tapping on Permissions, and enabling the Display pop-up window while running in the background permission (it might be in the category Other permissions). Here's what the menu looks like: