Do a quick check of all your Neutrino peers under Embedded Node > Peers > Neutrino and remove any with high ping times (hit the stop watch icon). Lower is better. Under 100 ms is ideal. 200ms is still good. Under 1000ms should still work but may give you issues. You want at least two good peers.

Then you can trigger a rescan of your wallet using Menu > Embedded node > Advanced > Rescan wallet. Takes about 10-15 minutes to complete. Unfortunately, there is no UI indicator for the progress here, but you can track it under Menu -> Embedded Node > LND Logs