I recently upgraded from 2024.1.1 to 2025.0.1.
It would not connect to the database. After several retries I found out the upgrade was updating some Integer to BIGINT datatypes. I understand it may be hard to estimate the actual time, but it seems like you could check the count of records it was going to update and at least display a message if it is anticipated to take a long time.
Also I found no mention of this in the installation instructions, just a heads up would be nice or some indication it was actually doing something.