bitcoin amounts, and it is important to note that doing a hard fork does not have anything to do with having other bitcoin measuring units because it is simply about placing decimal places rather than doing a hard fork.
This is simply not correct.
At the protocol level, everything is measured in satoshis. There are no decimal points; only satoshis. You cannot move a decimal point in the protocol because there is not one to move. Coins are defined as 100,000,000 sats. Amounts, outputs, block rewards, fees, everything, is denominated in sats.
If you want to introduce a unit smaller than the satoshi, then it requires a hard fork. A hard fork is a fork which makes things which are currently invalid, valid. If I tried to broadcast a transaction right now spending some fraction of a satoshi, it would be invalid and would be rejected. To makes this invalid transaction valid, we would need a hard fork to introduce smaller units and re-denominate everything in to these smaller units.