There’s nothing saying that the ARM macOS port isn’t to blame.
Porting operating systems is hard.
It's very likely future software updates can help address these issues.
Honestly, the machines haven't had wide deployment in the field for all that long for Applications as huge as Photoshop. It takes time to discover, fix, and redeploy things like Photoshop. And it's not like Photoshop never leaked memory on an x86.
There is. People have been running ARM macOS for about a year and I haven’t seen this complaint before.