Peel it again then silicone some waterproof trim in place.

Tile wouldnt help. You still have to caulk between tile and tub. I would just consider it a job that needs to be done once a year. The kids will grow up and the house will stop settling after a while, and it will most likely last a while longer.

I had the same problem and was given great advice from someone here. I removed the caulk and replaced it with 100% silicone. But before I redid it, I filled the tub with water to make it heavier and then did the silicone. That way it does not pull away from the tub. I did this several years ago and it has been fine since.

Remove every trace of the old silicone, then clean both surfaces with acetone. If the tub is a composite material, use denatured alcohol instead, and clean 3-4 times. Use a fresh rag or paper towel for each cleaning.

Both surfaces must feel "squeaky-clean" before proceeding. After touching the surfaces for the "squeak test," re-clean with denatured alcohol to remove any skin oils. Then re-caulk.