I bought a Bluetooth speaker and only Apple devices can use it smoothly, my Android 8/9 phone remembers its paired speaker but can't connect it unless I unpair

I bought a Bluetooth speaker and only Apple devices can use it smoothly, my Android 8/9 phone remembers its paired speaker but can't connect it unless I unpair them, press speaker's pair button, pair my phone again every single times. I plan to buy a DAC that support Spotify connect.