I'm a GRAMPS user since 2019. Also use Ancestry and have over 13,000 people on it. I have downloaded the Ancestry stuff into GRAMPS and have taken a look for what it produces. Not too good.
For a clean upload to WT, each profile would need to be cleaned up a lot or the junk will be uploaded and need to be cleaned up.
My suggestion, download to the program of your choice, clean up each record, tag it, then when you have 100, upload them to WT.
Do a trial of a very few first to make sure you have done everything in the program to create a good upload process.
For example, the upload needs to contain a Birth and Death record when you only have a Baptism and Burial events. Also, the Place names need to be correct and complete. Dates need to be in the 15 Feb 1830 or 1830-02-15 formats. I now know how to enter everything needed in GRAMPS which produces a very clean upload to WT. It took about 6 changes to my process before I got it right. Good luck.