06 Civic EX sedan replaced the battery and alternator. Getting high RPMs

Hello. I’m new here, first post on a forum ever. Forgive me if I sound dumb, I’ll do my best to give you the best information. On a budget and was never taught much about cars.

My car is used mostly for gig work so I try to take good care of it. Regular oil changes with synthetic Its a 06 civic ex sedan automatic. 138k. Replaced the starter last year.

So I was making a delivery and my battery light came on. Got to the drop, but when I got back in the car all the lights were coming on and off. Basically the electric was trippin. I drove it out of the housing community, stalling on the way before I pulled over. Turned the car off. When I tried to restart it, got a clicking.

Battery was a goner. So I replaced it with an interstate battery from Costco (has a 3 year warranty) Everything was back to normal. No lights, nothing. On my 4 mile drive home. Battery light comes back on. Had the alternator tested, it was bad too. Replaced that with this. (I know)

Alternator Compatible with/Replacement for Honda Auto And Light Truck Civic 2011 1.8L https://a.co/d/9Y1Nbk6

Now there aren’t any lights (no cel, no battery light) but I’m feeling like when it shifts for a third or fourth time. The rpm’s are going too high. Like 4-5k+ rpm. When it does shift it only drops to like 2k. If I let off the gas shortly after shifting, it drops to almost zero. Tried turning on the headlights and maxing the AC to see if the battery light comes back on or the display is effected, nothing. All is well.

Did I ruin my transmission? Or the computer? Yes the alternator isn’t the best. I get it, is that what’s causing my problem?

Haven’t had transmission issues in the past. Any help would be greatly appreciated. Thanks in advance.