Suggest to check various websites, see what that have. EBay auto part, Rock Auto, & Dorman are where I’d start. The simplest solution may be to just buy 3 copies of the same stock replacement part, and replace them as they break. The problem of plastic parts in mechanisms on the inside of doors is not limited to Hyundai btw. I had to replace* a problematic door handle part on my Corolla, b/c the plastic part broke when I attempted to remove the handle to repair the lock mechanism. It may be the case that this particular part is more vulnerable to breakage on a Hyundai Tucson than the same part for a Honda or Toyota. In that case, maybe buy a Honda or Toyota next time.
- Actually I didn’t replace the broken plastic part. I repaired it using JB Weld epoxy glue. So far so good, 4 years later. Might want to lube the part next time you replace it, a little dab of moly grease maybe. Might help it last longer.