I think purely looking to vanilla OpenWrt 128M still is okay.
But it is expected to use it as a normal router, theres still room that you can still fiddle with packages but not those with lots of adblocks.
It will however be interesting what wifi chip it uses the wireless blob will get loaded in memory, I hope they avoid wifi 7 all together because these blobs actually should require more ram, more the 1gb ram in my eyes, Beryl 7 had 70% usage on 512M.
Older chipsets have much more size reduced on those blobs.
What I'm also interested in is if amneziawg is a bigger counter part or if it can still hold a good footprint with memory size.