Just a heads-up in case you weren't aware:
There is no RAM in the new Macs, since Apple Silicon introduction a couple of years ago. Apple Silicon is a SoC (system on a chip), basically no motherboard, everything is on that 3-nanometer chip (the M3) and yes it's not user upgradable for obvious reasons.
The RAM is replaced in that instance, by something called Unified Memory Architecture on the Apple Silicon chip.
The advantage of that UMA on a SoC is that it creates one pool for sharing memory and data between all of the chip components, therefore eliminating the need for copying and moving data to a different part of the motherboard where and when needed. This results in faster and more efficient performance.