Someone mentioned, and I really agree with this idea, and that is to practice with an identical pistol and shoot your actual carry gun as little as possible.
However, if you are going to shoot just your Gen 2, and you really shot 20K rounds and only changed the recoil spring, you should change EVERY spring in the gun. Glock recommends changing the recoil spring (RSA) every 3000-5000 rounds. It's no wonder, at this point, you started having malfunctions. You were 6x or 4x overdue on the RSA.
Your mags need attention too. Get one specifically for carry if you don't want to buy multiple. Or, at least change the springs on your mags.
Get the magazine disassembly tool and a 3/32nd punch to have the ability to disassemble your Glock.
Don't be nervous about disassembly. Watch videos. It's rather easy once you do it.
You could also cut off the part of the slide stop that hangs out of the frame if you are worried about inadvertently activating it. Doing so will still allow your slide to lock open on the last round.
Please do learn to take the slide apart because your striker channel is probably very dirty, has bits of primer/brass chunks, and needs cleaned out. Don't oil the striker or the channel. It needs to be dry. Clean with alcohol after using any other cleaner in there.
Besides, your striker spring and striker cups should be replaced too.
Order the parts and watch videos on how to.