I would never say no to using older hardware. Yeah, it’ll be like punishing yourself. But you learn a shit ton.
I recently started self hosting. I started on a PC with the same specs as you’ve said. Booting was an issue. And tons of stuff always broke. But i learnt a lot. And then there was a time, when i genuinely thought i could do better and switched an old laptop with decent specs.
Pi’s are very expensive and too dang low on supply.
So always make do with what you have. If it’s your first home lab, then yeah go ahead. In a few months switch