I've been uploading my family a few generations at a time. So for example, on my mother's side perhaps her, her parents, and their parents, and including all descendants for 2 generations to catch all brothers, sisters, etc. I will then look at my WikiTree end-of-line folks to see where to start for the next GEDCOM export/upload. It's slower, I know, than uploading thousands at once, but personally, I appreciate the opportunity to review the folks I've uploaded, clean up their profiles, and perhaps find information that I may have missed previously and forgotten I didn't have (like marriage dates, etc.)