I am not sure it is not DIY, lots of people have done it themselves.
The fact you are asking suggests it is not DIY, needs a lot of research and focus.
K1 or CRI well IR1, I prefer IR1.
So marry, file the I 130, after 18 months or so goes to interview, has a 10 year ban, will be allowed to file a waiver, I 601, they seem to take about 2 years to process, not quick or cheap, if they need further help they should join.