Yes, it would be low end. iMac is not just CPU - its overall package and a lot of people need the GPU power and not just CPU. The 21" was always crap device when it came to GPU. I guess it was simply due to the limiting form that maybe didn't allow for more TDP.
So, maybe what Apple can do is ditch all model in the 21" category and just keep this one as as you mention it will be faster.
However, it will still be low end model. 27" currently nukes everything when it comes to GPU processing so until Apple can at least match 5700 XT then its pointless to talk about "powerful" chip.
Anyway, I think we are reading too much into the iMac thing and I'm starting to reverse my excitement about iMacs tomorrow to just "Hey they might show us a decent low end model but thats it"
I don't mind waiting though as I feel the M2 or so needs a bit more time so the more time passes the better likelyhood that we will get some serious 27-32 machine that most of us will be happy with for years to come.
This alleged 24" will most likely not be powerful enough.
How would a M1 iMac 21.5" be low end when it beats all the other iMacs except 27" with 8-10 cores in Geekbench 5? It would be weird to have such an iMac at the bottom side by side all the other more expensive iMacs unless it only has 4-6 cores instead of eight.