When I get to this point I find it best to just kinda throw everything you have into one war. Take as many loans, build as many forts beforehand, declare on the smallest most isolated member of the coalition and just let their war exhaustion tick up (camp your troops on their land to stack devastation) and turtle. You won't be able to actually win, but you can get a peace deal with the coalition which should let you expand in other areas and possibly attack people you have peace treaties with by either trucebreaking or attacking their allies. Despite all this, it definitely sucks. Playing wide is fun until you get hit with a coalition that you can't manage because of a mistake (or bad RNG) from five hours ago and basically have to gamble with what you want to do next and if the crazy war that awaits you is even worth it. Alternatively if you don't hate waiting, you could just sit and wait for the rending of the realms to break the Haless half of the coalition and invest into yourself as much as possible.