You might want to check out this thread:
I’m not convinced that a newer device will make a noticeable difference in the case of simply driving a single synth. You will more likely notice a difference (for your use case) with the devices’ overall ability to handle multiple tasks simultaneously.
For example, on my older mid-2015 MacBook Pro Retina, I can’t run a DAW session, video conference and screen recording at the same time with a low buffer…maybe it would work at 512 with very little performance headroom and some latency where it compromises playability. But that wouldn’t be a problem on my 2020 M1 MacBook Air even at 256 and maybe even at 128.
That said, the older laptop runs MG2/3 fine and I don’t think I could pick which machine I was running through in a blind test of MG2/3 and a lead synth only. (I mean based on playing/physical sensation.)
But that’s just my take based on playing with the software a lot and trying to break it 