Once the priority and frequency are set on any of the urls in URL
List (by GSC after the first crawl and by you thereafter) they don't
get changed through subsequent recrawls. You can change any yourself
as you see fit prior to generating the sitemap.
Don't start the process in automated mode. Do at least one run
manually, where you set all these things and do a first manual upload.
After that go to simple automation one step at a time.
Only after you are satisfied all will be OK should you go to full
automation and maybe scheduling the runs using whatever scheduler you
have available on your computer.