A fork is actually a 'changed Bitcoin'. So yeah, you can change it, but the next question is whether the network accepts or adopt it or not. If not, then your 'new Bitcoin' will fail.
Bitcoin supply is 'huge' already. As Danny pointed out, you can divide it into smaller numbers. Whether those small numbers worth something or not would be answered in the next few years. Surely this supply thing would no longer be a problem when 100 sats are equal to a dollar or something similar.
People should really look up this way.They do just focus on that 21M overall supply and do treat that 21M whole coins would be on circulation in time of full adoption
without even thinking that it can be breakdown into small units.As said the supply is just really sufficient and theres no need for some protocol change just to increase or do
ask for larger supply. I agree on what you have said about those shitty forked btc coins out there, they havent been even supported even they are much better when it comes to
specs compared to btc itself.