I wouldn’t go back further than the 8th gen intel minis that the m1 replaced, just to get a bit of longevity out of them (including macos support) and the price

I wouldn’t go back further than the 8th gen intel minis that the m1 replaced, just to get a bit of longevity out of them (including macos support) and the price for those is close enough to the refurbished m1 models that I don’t think it’s worth bothering about intel minis.