Children are adorable at that age. However, if you hate playing with Barbie etc., then I suggest you carry on as you are, ie playing for a while, then doing something else. Your granddaughter needs to learn to amuse herself some of the time. If she doesn’t, the whole family will be held to ransom. The trouble is, you may encourage her to play alone for short periods, but I expect her parents will carry on as they always have.
Like you, I wasn’t a fan of the things your granddaughter wants to do, so after doing her choice of play for a reasonable time, I did tempt her into doing other things.
Sounds to me like you are doing a good job, playing with her, taking her out etc. The only other thing I would say is, she will grow quickly and this won’t be a problem for ever. Make the most of it. My beloved granddaughter is now 23 and I would give a lot for her to be three again, although I remember wishing she was older at the time! There’s no pleasing us sometimes, is there?