Capturing all the extra carbon from the atmosphere is not as expensive as it sounds like. It can easily be done by a few rich countries in very few decades once we stop adding more there every day.
Recycling nuclear waste is one of those problems that should be easy but nobody knows what the easy way looks like. It’s impossible to tell if some breakthrough will make it viable tomorrow or if people will have to work for 200 years to get to it. But yeah, currently it’s best described as “impossible”.
Yep, “insane amounts” of power like you what you get by investing something like 1% of a few countries’ GDP in PV panels.