@Pauly Yeah, Avis brakes to have a bit of a dodgy reputation. If you don’t know how long since they were serviced, give them a bleed, or get a dealer to do it and check the seals at the same time. I occasionally get a stuck piston which can be sorted with some silicon spray like Fork Juice, pushing the pistons in and out a few times. This relubricates the seals.
If you set the rebound on the shock too slow, it is effectively packing down, but being old it is just worse than normal. Run it at max 50% of clicks from fully open and you should be fine. You would never want to run rebound at near max for any reason I can think of. Get an independent dealer to see if they can service the shock as it won’t really be worth buying a new one for that bike. A Specialized dealer will only be interested in selling you new bits or a new bike
Not having a lockout on a shock or fork is a good thing. If you forget to release it before heading down you can blow the seals. A climb setting which effectively winds on lots of compression damping like the Fox fork is the way to go. And just forget about the travel reduction function on the fork. Most modern forks don’t even have them. Personally I never bother using the climb switch on the forks. They. Don’t really bob unless you are doing some really serious out of the saddle mashing and are racing, plus it’s just another thing to forget when you start to head downhill.
If you don’t know which local bike shops to trust, sign up to Singletrackworld and post a request for recommendations. The local independent bike shops make their money from looking after older bikes, but like car dealers there are good ones and bad ones out there