If you swap BT versions then you usually have to turn buds off then on.
Obviously buds only connect to 1 thing at a time so you have to disconnect to then allow to connect, some laptop chipsets will auto reconnect and so thus the poor buds end up being fought over by two laptops so also a good idea to turn off bluetooth of other devices to stop them. Some used to multipoint buds have to remember to do this manually.
Reset also usually helps, in part due to the above point being missed and the buds are kept being reconnected to some other device as you didn’t disable their bluetooth.