Well, you won't be buying your 9 mm ammunition at Walmart any longer it that is a factor.
I have a set of Tech sights on one 10/22. The Tech Sights for the 10/22 all use an AR type front sight post that screws into the sight body. The front post included is an A1 style post with 5 detent notches on the flange of the front post, but the diameter and pitch of the threads is the same as for A2 front sight posts (which have four detent notches on the flange), so you can swap out the front post for any A2 front sight post. The post that comes with the Tech Sight front sight is basic black, but you can find A2 front sight posts with fiberoptic inserts pretty easily, and you could use those with the front Tech Sight.
Although I have never used them, a lot of people seem to like the Williams sights for 10/22. The Ace in the Hole set includes a fiberoptic front sight blade with an aperture type rear peep sight mounted at the rear of a Picatinny rail.
https://williamsgunsight.com/product/ruger-1022-with-fiber-optic-front-sight-ace-in-the-hole/
The Tech Sight TSR 100 and 200 rear sights mount in the rear holes tapped on the top of the 10/22 receiver for the accessory rail. If you mount one of them, you will likely have difficulty mounting a scope rail. Tech Sights does sell a TSR 200 RL rail-mounted rear sight that will mount on the central 3/8" dovetail portion of the Ruger accessory rail and can be easily removed. The TSR 200 RL will not mount on a Weaver or Picatinny rail, however, so you would be stuck with the Ruger accessory combo Weaver/dovetail rail or a 3/8" tip off rail if you decided you wanted to mount a scope.
The idea of mounting a scope while still allowing use of iron sights sounds better than it usually works out. The rear sight often gets in the way of the ocular bell of a rifle scope unless very high rings are used. There are see-through rings that theoretically allow you to get a sight picture with your iron sights below the scope. But the scope usually winds up being mounted so high you can't get a decent cheek weld. And if you pad the butt stock to raise the comb height you can no longer get your head low enough to use the iron sights.
Also scope rails that end at the forward end of the receiver, like the Ruger accessory rail, may not allow you to get some scopes mounted far enough forward for proper eye relief if you want to shoot in a prone position.
As for ammo, different rifles seem to like different ammunition and you may need to experiment. But stock Ruger barrels generally seem to do well with various types of CCI 22lr ammunition. CCI Standard Velocity is very popular and I would certainly try it. CCI Mini-mags are higher velocity but also quite popular. CCI Green Tag is a bit more expensive and some have observed slightly better accuracy. I have had good luck with Aguila Super Extra High Velocity although others favor the Aguila Standard Velocity. Another variety that gets a fair bit of lip service is Blazer. There are more expensive types of "match ammo" but unless your barrel has a match chamber (it does not) you may not buy any greater accuracy for your money.
If you buy the loose packed bricks of 22lr ammo you can generally expect not only less accuracy but also at least a few misfires per brick. But for casual plinking such ammo might be "good enough". I have had a little better luck with Federal Auto-Match than I have had with Remington Thunderbolts or Golden Bullets.
Projectiles can theoretically lose stability and accuracy when they pass through the sonic barrier dropping below the speed of sound which is typically around 1125 fps at sea level. 22lr projectiles loose velocity pretty quickly and a projectile like the CCI Mini-mag that leaves the barrel at around 1235 fps will have slowed to below the speed of sound before it goes 50 yards. The idea behind a standard velocity cartridge is that it starts out below the Mach 1 so it never goes through the transition. But I am unsure as to how real this effect is. I know of people who have very good results using CCI Mini-mags at 50 yards and beyond. I have three Ruger 10/22s and they all cycle standard velocity 22lr ammunition fine. Your results might vary but you will surely know by the time you shoot 100 rounds.
The "high velocity" ammunition will not damage your rifle. I would probably avoid the very light "hypervelocity" ammo because there is no reason to use it for your purposes. As for self defense, I would only use a 22lr chambered weapon as a last option, but if I did I would use high velocity round nose ammunition.
The Volquartsen Exact Edge extractor will not hurt your rifle or cause accelerated wear. Many people use them including me. It is the claw of the extractor that grabs the rim of the cartridge case that has a "sharp" edge.