The jacks really aren't expensive. I replaced all 4 on my trailer just because they were getting rusty.
The ones that come on the TM have a hard to use driver arrangement and are rated @ 3500# each. These new ones use a standard 3/4" socket (included) that I put in my drill motor. Makes lowering and raising the jacks a breeze. The new ones are rated @ 6500# each.
These jacks fit in my original screw holes too.
https://www.amazon.com/WEIZE-Trailer...7-93deae8f9840