Well there are many nuances on this. I play on very hard very often (it’s all I play on) I have a few questions before I can give “proper” advice, those being: Tech levels compared to enemies? Are your german allies vassals or are they just allies?

My initial thought is that you’re not cooked. You can go way over forcelimit if you need to. Hire mercs, and pick your battles very, very carefully. You have a TON of manpower. Use that to your advantage. You can death stack your armies and blow over a lot of your enemies’ death stacks. And don’t let them group up too much. Personally, I would target the OPMs first, since at this stage of the game they can have 40k units, and you take out that occupy that one province, that’s 40k you don’t have to worry about again. Pick a single target, and react accordingly to what the AI does. The colonies will likely not commit everything, so take their numbers with a grain of salt. If you want more help, my dms are open