Keeping a Smart Doggo Busy

Hello! My husband and I rescued our terrier mix, Artie, a few months ago and are looking for tips on keeping her busy and mentally stimilated. She has a lot of energy and is very smart. She also is pretty timid (i.e., scared of loud noises) and not particularly treat motivated. We recently bought her a treat ball and she is scared of the noise it makes when it rolls. Stuffed kongs work for a few minutes but she is over it pretty quick (even if treats are left inside). We take her on walks/to the dog park as often as possible, but when the weather is bad and she has to be cooped up inside she gets ancy. Playing fetch/tug of war seems to be her favorite inside activity, but is there anything that she can have to keep herself busy when we aren't home? We've looked online and haven't seen many helpful ideas so figured this is another route to find ideas. Thanks in advance!