I went to start it up and there was nothing, no sound, no click from the starter?

Some background info that may or may not be relevant to the problem. A few months ago, I had another key made at Ace Hardware because my old FOB key kept falling apart, the FOB itself hadn't worked for a couple of years, so I always had to manually lock and unlock the door anyway. I told ace I just wanted a key and didn't want another FOB key. They made a new key and programmed it into the car since that's what has to be done when copying a FOB key. Everything worked fine for a couple months until a few days ago when I went to get out of the car the doors were locked and at first seemed like they didn't want to unlock, when they did and I got out the car alarm went off, unhooked the battery to get it to shut off, if I hooked the battery backup it would come back on. Finally, out the key in the door lock and locked and unlocked it and the alarm went off. Had the battery unhooked long enough that I did have to enter the code to get the radio to work again. But then I went to start it up and there was nothing, no sound, no click from the starter or anything. Because of the weirdness with the alarm I decided to try my old key that had the FOB, and it started up with it. Then shut the car off and tried the new key that I had been using and it started up with it also. Wasn't sure what had gone wrong but thought maybe everything was reset now. It drove fine for a few days, drove it quite a bit and no problems. Then went to start it up this morning and nothing no sound no clicking or anything. Thought I would try the old key again but it didn't work this time. Tried it several more times with both keys and nothing. A few hours later checked the battery with a multimeter, it was getting 12.6 volts, and in the battery load test on the multimeter it got 12.6 volts as well. Tried starting it up again (with the new key) to see what would happen and it started right up. Shut it off a couple times and it fired right up just fine when I restarted it. Had a similar problem on a 2000 Chevy s-10 a few years ago where it wouldn't start occasionally (no sound or anything when turning the key over), and then after a few minutes, sometimes hours it would start. Ended up replacing the starter myself (after a shop had replaced the ignition switch that didn't fix the problem), and that solved the problem. So, thinking it might be the starter, but wondering if the alarm system weirdness the other day could be causing the problem, since that's the first time it happened.