I would like to point out the iPad Mini 6 is able to run Stage Manager on it's 4GB of RAM.To run stage manager you only need 6gb of ram on an iPad… So the iPad mini could do it but it’s not enabled by apple.
Don't think stage manager will be useful on a smaller display.
It is very useful on a small display. I can make a few clusters of 2-3 apps and swap between them really conveniently. It sucks that this isn't a feature that is able to be opted into in the settings. It will be a sad day for me when Apple patches the method for enabling it.I can’t imagine stage manager being pleasant or very useful on a 7 inch display, honestly