There were a couple of factors why it took a week:

1. We wanted to avoid downtime, so the pg dump was slowed down because it was happening alongside production use of the db

2. We abuse postgres in a couple of ways (too many large json columns) which makes it harder to export and import

3. We were moving between cloud regions and cloud providers.

4. I'm a bit of a database ops noob (part of why supabase was appealing in the first place) so I had to learn how to do all these things. Like burggraf said, a lot of that week was planning, trial and error, test runs, mistakes that would cost full days, etc.