These machines are great. I still use my 2015 rMBP as a secondary. It's a little slow now but a couple years ago I was still running Solidworks (in Bootcamp) on it with minimal issues.
As a data point, I still use a 2013 Mac Pro as my primary desktop, and I've been using Sonoma on it for several months, have been able to install all Sonoma patches over-the-air on release without incident, and have only experienced a single, trivial problem: the right side of the menu bar occasionally appears shaded red, in a way that doesn't affect usability; switching applications immediately resolves the problem (the problem appears to be correlated with video playback).
Not just that, for high res stuff or modern codecs like AV1 or h265 is probably not supported at all in a 2012 device without updates for so long?
Even if support was possible it would be software encoding and even short clip it can take hours to render ?
I would happily use an older device for development a lot of dev work especially if not frontend or UI usually i can use any laptop just as a terminal, but UI or video editing I wouldn’t be able to.