iPad bluetooth keyboard lag

I have an iPad Air 3 and Omoton bluetooth keyboard. The duo works just fine for for 30-60 minutes, but after that, it starts to lag noticeably. It doesn’t stop until I restart the iPad itself. When I turn off the keyboard and turn it on back, iPad wont connect to the keyboard back. Forgetting and pairing as a new device wont work too. Anyone experiencing this? I did some google and read that it is because keyboard is bluetooth 3.0. But almost all bluetooth keyboards are BT 3.0.

Im on iPadOS 14.4. Help me out. Thanks.