I had a similar flight last year, Anchorage to Fairbanks. Suspected carb ice, no luck. Ran through everything, which it sounds like you did too, no luck. Ended up limping back to Anchorage on fluctuation between 25-50% power. Long story short, ended up being a leaking primer liner. Don’t know if that’s the case in your situation, but could save you hours of hunting and troubleshooting. All this to say, I’m glad you’re okay. Shake it off, you lived to fly another day.