There are well made toys that give their brains a work out but are able to cope with the enthusiasm of Labradors. We used Kings, the ones where you can stuff a hollow with food or cheesy mash, peanut butter mash, or whatever, all the better if you freeze them. They keep them occupied and stimulated for quite a while. Adolescence undoes all this great puppy training. It's back to basics, calm, clear consistent instructions, not a load of words couching the one important one (eg 'stay'). Labs are usually joyful lumps of happiness who act without thinking until about three we've found, but are very trainable with, as you say, tasty treats. Ours really have never discerned between a tiny bit of something tasty and a big bit. The tiny one with praise does the job and means repetition is possible, which really is the key to success. Good luck! One of ours , who I bred, will be fifteen next month, a still sprightly dear, her sister a red fox (much more hyper but amazing to train) is four. Love them to bits ♥️