I am FP-C and CCP-C certified. I work as a flight paramedic.

Where I used to work, starting pay for critical care paramedic would be about the same as a top step/highest paid paramedic, about $100k annually in the San Francisco Bay Area. I work all over the country. Sometimes there is no pay difference between a paramedic versus critical care paramedic. Some places recognize it (eg CO, OK, and a small handful of counties in CA), but a lot don't. In some places, paramedics, just regular paramedics, will be given a ventilator, IV pump, and can function as both roles with little to no additional training unfortunately.

Usually you have to get either a CCP-C or FP-C cert. That is just a test with no class or prior experience required. You can also take UMBC CCEMTP course, which is a class, but I don't know much about it.