Various people have already ported zynth to Pi4 9 (as far as I’m aware). Obviously the current case is built around the Pi>4 so a little judicious modding would seem to be in order, going forward, Id’ be interested in heat as an issue, but personally if the Pi4 is thermally stable with an audio card strapped on it’s back, I’d certainly expect a Pi4 in a zynth case to be eminently viable.
Certainly the extra memory is a real boon, but from a software point of view the process is very much travelling down the road althou’ jenkins is still sulking on our behalf … https://jenkins.zynthian.org/
I’m just describing what I believe is out there but
Quite how long before this all hits the world is a Barcelona bound issue . . .
With heat as an issue, I would put a stacking header between the Pi and the HiFiBerry and extend the standoffs moving it further from the pi. Then there may be room for a fan.
or perhaps a blower off to the side blowing between the pi and the HiFiBerry.