I recently bought a M1 Mac Mini with 512 SSD, I have it stacked on top of a 2010 Mini and 2012 Mini. Wife got Turbo Tax and it wouldn't run on my 2017 MacBook Pro, because I am not upgrading to latest O/S because it'll clobber my older apps licensing. Very impressed with the M1 Mini, runs everything no problem, and fast. I keep the older models, each having it's share of older apps and uses. My 2010 Mini is dedicated to 3D printing, the printer ties up the machine for hours at a time. I still use my 2010 and 2011 iPads. No need to toss out perfectly functioning old Macs if you have a need for them, although you should get newer ones after a few years for the newer features. I keep them all networked to share files. (As for cost, selling Apple shares pays for it all.)
I run a 2009 MacPro with 5 8T HDs running in a Soft Raid Pro that I use as my main machine. Have another one I am going to press into service as a Raid drive. I am tired of losing data with the Drobo I have. I have had 5 of them and have 1 still working. Supposed to be able to transfer raid sets from one Drobo to another Drobo but I have never found that to be true. At least with Mac OS running Soft Raid I can replace a drive whenever I want to. I control all the Minis from my Mac Pro, no sweat even the M1. I am beginning to hate Apple’s efforts to protect us. Disabling SIP is a pain now.😀