I was recommended a distro that doesn’t use Gnome (Lubuntu). The system I was working with is very old and some light research made it seem like Gnome is pretty resource heavy.

How old are we talking about? 10+ years ago I was running Gnome3 on decent hardware of the time, and everything was snappy[0]. Now all the OS software got faster since then, so everything is still snappy on that thing despite that hardware now being old. Similarly that laptop came with Windows 7 and that was snappy, and the Windows 2021 LTSC on it is also snappy[0].

0: I care about responsiveness, so I've always disabled animations on every device, so I have no experience if some animations can run at 60fps on some hardware and 30fps on others.

I think a lot of times recommending Lubuntu or other niche distros to first-time linux users is a mistake.

Instead one should recommend using KDE or Gnome and turning down all of the graphical settings if needed to improve performance.

I think it comes from the idea that you should install Linux to get more time out of aging hardware.

Yeah, but for first time users I maintain it'd be better to risk potential slowness than "fast but unacceptable user experience".

Fully agree. I don’t really know what the user groups are doing these days? Are installfests still a thing?