Upgrade path???? Mine was more of a trip stumble fall thud dislocation groan and then some oozing.
T3i to 5d3 and now 1dx (that is for sale fyi) .
Just yesterday i looked up what the mf43 price/conversion might be.
I got the 1dx (used $3k and it still has barely 4k acuations) for a trip that didnt happen.
I dont do low light sports etc. Kayaker thought i was a birder only because that is what is world class in my neighborhood.
I have yet to print a 4th image. All my image consumption is on me 55" 10bit samsung 4k tv that is now my monitor. Soft proofing colors goes a long way to make 8 bit look like 10 but it doesnt quite get there.
All of this to say that bulk of FF is more hinderance than IQ for my purposes.