Is this a tough fix? something I've never tried. I don't think it's a deal breaker, but I don't know what I'm getting myself into.
I think it's a pretty basic fix with basic mechanic skills (properly using tools and having the right tools always makes things easier) and fortunately there are a lot of good references like on Youtube and I'll link a few below to get you started.
Most u-joint jobs I've done were back in the 1960s and a few in the 1980s/90s. Except for once or twice I've always done them one at a time from under the vehicle with twe vehicle raised enough to give me room to crawl under and without completely removing the entire drive shaft and doing the job on a work bench.
HOWEVER, in this case I'll recommend removing the entire drive shaft because it's easier to see what you are working on and you'll better be able to properly identify the exact size of the u-joints you will need for replacement (as there are several sizes) AND if you encounter a problem you can if needed you can take the 2 individual sections of the drive shaft with the u-joints and hanger bearing (which also has a u-joint) to a parts store and usually SOMEONE there will be competent to properly advise you. Where I live NAPA stores seem to have older personnel with more experience. Secondly they can confirm from the parts what size u-joints and hanger bearing you will need, so you won't end up ordering wrong sizes. You can also take the driveshaft and u-joints anywhere to get advice from an experienced mechanic, such as a transmission/drive-train shop or a shop that works on some pick-up trucks including diesels, instead of just tiny little cars and minivans.
Videos: Chris Fix has excellent instructional videos so I'll start with one of his:
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IF YOU WANT TO LEARN A LOT (or not, I still recommend this multi-part series)
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