One challenge will be the uncertainty in models. It's (comparatively) easy to say "this will reshuffle climate so that our system which assumes current climate zones will be in trouble" and much harder to say which areas will flood and which will burn.
There may be work with doing refining those models.
There may also be things we can do to increase flexibility and resiliency without knowing exactly what's coming.
But it'll be tricky.
(somewhat weakly held)
Climate outcomes aren't binary (succeed / fail) so the question is always "should the next dollar go to mitigation or adaptation?" irrespectively of whether specific targets are reached.
The bar for adaptation actions to be the most cost-effective seems quite high, as most adaptation options seem quite localized actions (hard to scale and hard to be extremely cost-effective), whereas the best things you can fund on the mitigation side will have global effects (such as changing the trajectory of clean energy adoption).
One exception to that could be stuff like accelerating more weather-resistant crops if that is neglected.
I think overall adaptation is more neglected than mitigation. There is quite a bit of work on drought and heat tolerant crops. However, there is very little work on scenarios of abrupt climate change, such as the shutdown of the thermohaline circulation that could cause abrupt cooling in Europe (and has in the past). There is also very little work on backup plans for extreme weather on multiple continents causing a multiple breadbasket failure. And there is very little work on adaption to extreme climate change that occurs slowly (over a century). ALLFED is trying to fill these gaps.