Page Generation Time still valid?

In Piwik Pro’s default System Dashboard about Website performance, there is the “Page Generation Time” metric (and it shows the dreaded average, which leads to nothing but confusion at clients because single peaks because of single weird browser behaviour lead to extreme(ly irrelevant) peaks in the data. But that’s not my main problem.)

This metric however is not used in the Page Timings Report, which is already a bit puzzling…

According to List of dimensions and metrics | Piwik PRO help center , “Page generation time” is “The page loading time on the visitor’s device.” – a very obscure definition that says everything and nothing. I have no clue how this metric behaves compared to the other performance metrics. And yes, I have also read this thread, but I am not any clearer in my old brain what exactly “Page Generation Time” means:

In that thread, @kuba says sth that could be interpreted like “Page Generation Time is deprecated, we need to clean it up”. But that was 2022, and Page Generation Time is still there and in all clients’ system dashboards. Is this metric reliable?

In our case, it shows trends that none of the other Page Performance metrics really seem to back up, but that interpretation could also be challenged. I just want to make sure we are not wasting hours and hours trying to figure out what may be the cause for an increased Page Generation Time when the metric is deprecated anyway.