DIYable? Yes. Skill level? 4. Replace both? Depends.

The PCV system is completely separate, do this as two different jobs. First is cam seal. Your car probably has a VVT on the exhaust cam, that raises the difficulty exponentionally and also requires a cam locking tool on the rear end of the engine.

I would do just the easy one, along with a new Tbelt, tensioner and pulleys, Sbelt as it is oiled as well.

Line up the 3 timing marks. Clean the cam gear. Paint the 3 bolts that hold down the cam gear - the gear has oblong holes and needs to be put back exactly as before- the paint is to mark the bolt head positions.

Cam seals for the front are cheap. Tapping them in with a large socket, just be careful that you don't tap them in too far.

Take the belt off after the 3 bolts have been loosened, but not loose! 1/4 turn is just fine. Remove the Tbelt. R&R the seal. Put the gear back in its original location. Torque to spec.

Finish the Tbelt job.

Then think about the PCV...
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My back feels better when I sit in a Volvo seat

I've not had this issue on my 850, but have had the clogged PCV. I'll throw out 2 suggestions, one of which I know works.

Leave he dipstick up a bit to vent the system, it works and bought me some time till I fixed the system.

Second, can you carefully tap the seal back in using a socket or small piece of hardwood, you many need to rotate engine by hand a bit to get all around it.

This could buy you some time with the dip stick pulled up a bit. I'll bet the seal with go right back in pretty easy, had it happen on an old VW once. Mike