I’m not an expert, others are much more well versed in these maters but… from my experience never count on the web interface succeeding, always be ready to rebuild from the command line. The recent PostgreSQL 15 to 18 upgrade detailed here was a slam dunk, you know you are not going to get away with the web interface upgrade.
It’s not that hard, consider the web ui upgrade a convenience, if it works… great but be ready if it does not. At least when it doesn’t work, it gives you an informative explanation for what happened and what to do to fix it. Many pro discourse admins around here would tell you not to even bother trying. My forum is small low volume, I can afford to gamble, you may not have that luxury.