As others have hinted at, you've really got a handful of questions to ask yourself:
1) budget
2) whats good enough quality of a result?
3) what type material do you want?
To do it right you need foam and at least some material.
It's also possible a spring broke or piece of internal frame came loose and that's where the support went. See broken springs in the frame all the time on 70s/80s c10 bench seats all the time during a rebuild. Sometimes it's rust, sometimes they just crack then finally break.
A shop may get pricey, and then your repair window expands if they need to repair/replace a broken spring/frame issue.
Also, replacement fabrics WILL sun fade and no longer match the rear seat, or, another seat. So if your goal is to redo 1/2 of the front only, be aware it may not match well at all within a couple years. Perfect example is replacement GN seat covers where the black slowly oranges, but becomes stark if only one piece was redone. For some reason the aftermarket can't come up with anything interior that lasts the way the oem stuff did.
Now, fabric is less forgiving then vinyl. If you put a full-vinyl cover on, and there's a slight, and I mean SLIGHT amount of looseness or pulling in a corner, once it's in the sun some it will tighten up and that self corrects to a degree. Fabric isn't forgiving like that to the DIY crowd. If the foam isn't springy enough, and the fabric has a loose spot, it's probably staying that way. If you're OK with that it's one thing. If you're OCD and know it'll bug you... well, better that a shop with warranty does the work.
Recovering buckets is different than bench. On a bench the seat backs and armrest have a zipper to aid removal with a bottom piece relying on hog rings to be taut. Buckets you need to tug harder and get tight all the way down. Then there's the plastic backed models that don't use fabric over the bucket seatback. Taking apart the pieces isn't bad on either. But starting with a cover sewn to proper dimensions is very important on all.
Final piece of advice I can think of? If going DIY, replace all the foam along with the pre-sewn cover. When they make up the covers it's usually based on a proper condition unbent/unbroken frame, with THEIR foam cover at full size and springiness.
If you re-use factory foam you risk it being worn/compacted somewhat, or, differing in size from what the new foam would be. You then run the risk of the new cover fitting loose somewhere. If time isn't a factor, you can try installing on original foam and see if it seems loose in spots before putting on rings. Then, if it does, ordering new foam in a second order at risk of having to wait for it to arrive, then swapping foam and reinstalling.