The fact that some sea level rise is baked in is true. As is some climate change. How much is still very much dependent on how much carbon we emit. If you are interested, this map allows you to see sea level rise projections by year with different future emissions scenarios. It also takes into account luck. Because all of these projections just give some most likely scenarios, and also give some odds on the less likely but still possible scenarios. The tail ends of the probability distribution the 1 in 10 chance scenarios. On one side we have getting lucky and it's not as bad. On the other end we have Armageddon. This is very much playing with the future of humanity and playing with fire.
Interactive global map showing areas threatened by sea level rise and coastal flooding.
coastal.climatecentral.org
Keep in mind, sea level rise, and the damage it does directly, is a small part of the overall picture of climate change. It will be food shortages and general destabilization of the world economy. No food. Chaos. Mad Max.
It's true that it will be very difficult to meet emissions reductions targets unless most of the big players are on board. But it's also true true that if everyone waits until everyone is on board, then we a doomed.