Talk me out of buying a new bike/frame

I've got my sights set on the GDMBR, NOBO in 2026. This will be my first long trip; I've done a dozen over-nighters and couple week-long trips and lots of other camping. My current bike is a cheap ebay carbon 29er with a lauf fork that I'm pretty happy with. I did the lower sunshine coast a while ago and I was losing the rear on the steep gravel climbs. My rear tire is a rene herse fleecer ridge endurance at 22psi; I don't like how squirmy it is on decent at lower pressure than that. I'm kinda in love with the idea of 29+ and my current frame only fits about a 29×2.2in tire; It won't fit a 27.5+ either. Also I have two sets of non-boost wheels (mtb and gravel) for this bike so a Krampus frame kinda fits the bill but I quite like how light my current bike is. Of course I can always spend more and get something lighter, but the point of this post is spend less, not more.

Do I need to improve my climbing technique, get a more aggressive rear tire, embrase the occational hike-a-bike, or are plus tires really as good as I'm imagining them to be?

I know lots of people will say my cheap carbon bike is going to explode and It's certainly something I've thought about. I guess I'm ok with what I regard to be a small risk.