I do not know motivation of the original poster but in my case a 2012 27 Imac serves me very good for my audio needs - except I m stuck on High Sierra due a lot of plugin problems and bad performance on newer OSX.
An M1 mini would mean a huge upgrade - even a i7 6 core would be more interesting if they were on same price range and similar potential for AUDIO needs - but this also would mean being out of the new apple ecosystem - and I have to worry about lefting all the stuff it works today behind in a exchange machine....some only X86 software too.
So M1 + Imac-monitor would be a parallel option if having TDM. Not to mention the cost (0.7k to 2.5k) for a new Imac / mini comparision and all first gen problems. I understand a fresh install stuff or updating , a new Imac would be suitable or even a spacialbility , hold a second display is for those who have a proper studio room - this would be a lot of hell tasks .Luna seems to be good option , then, if it works good - but I have to seehow good is it performance on display side - imagine if M1 doesn't work well and reliable in a modern market display offering , I imagine working on a old one mirroring via blutooth.