If the gun strips rounds form the magazine and always goes fully into battery I'd not mess with the recoil spring. Mass matters a lot more than spring force in terms of the bolt rearward velocity, so an M16 carrier and/or heavier buffer is an easy swap and easy to reverse if needed. Slamming it harder going forward with a stronger spring can cause feed issues as you are reducing the amount of time the mag has to get the next round into position and it could be hard on the cam pin, so I'm not a fan of "extra power" springs for anything other than magazines or maybe extractors. OTOH if your heavier buffer causes failures to strip the next round or failures to return to battery, then you may need an extra power spring, but I'd say instead that it proves your "over-gassed" hypothesis is incorrect and you should return to "standard".
An adjustable gas block is great idea if you are building, but as retrofit it can be a lot of work especially if you have a standard FSB. My suggestion is just shoot what you have with the cheap ammo and put the money you would have spent aside to buy an MGW "enhanced" 7.62 bolt if the bolt breaks.
If you have ignition failures, Model1 Sales sells an enhanced 7.62x39 firing pin (a bit more protrusion than standard) that I'd suggest trying before messing with hammer springs -- I've these in my 7.62x39 and 5.45x39 ARs.
I always say if you've never broken a gun you just ain't been shooting enough! AR parts are cheap and plentiful, keep some common spares and hand, fix anything that breaks and keep shooting. In various ARs I've broken bolt lugs, cam pins, extractor pins (weird one!) and had out of spec extractors that worked with brass cased but not steel cased. None of the replaced parts have broken. Reliability has a so-called "bathtub" failure rate curve where the rate starts relatively high with virgin parts (so-called infant mortality failures) slopes down to an expected low level, and then eventually starts to ramp up in the wear-out or end of service life phase.
