when i pair my Bluetooth Speaker (Anker Soundcore 2) with my “T95 Max” Box (S905, Coreelec 9.0.1) it runs sync at the beginning.
After some minutes it gets a 500ms delay.
And after 10-20 minutes it gets up to 750ms.
Its always the same, 0ms ,500ms then 750ms.
I also get this with my Anker (Been SO tempted to glue a white “W” to the front if it)
This has never been an issue for me. I always thought these things were basically just for playing music in the kitchen or whatever, so the delay hasn’t mattered to me.
I have a similar problem with mine, although in my case is always 300ms. What I do is to have a keybinding for changing A/V synchronisation so I can easily adjust it when using BT earphones.