After 7 days fully drained, phone will barely charge with USB-A cord.
I recently broke my pixel screen, and during the replacement I saw no reason to leave it on the charger, uselessly receiving calls and texts and what not, and since the screen was both black and unresponsive, I couldn't turn it off while it still had a charge. I let it drain itself, and left it alone until I had the replacement screen a week later.
Backstory: I have frequently used a 3.4 amp wall charger with the USB-C to USB-A cord, as well as a 20k mAh power bank with a 2.1 amp port, and they both work just fine. Even with the USB-A cord, I usually got "rapidly charging" with the wall charger, and if temperature and power level conditions were right, I occasionally got it with the bank as well.
After the screen replacement, the pixel still charges just fine with the 3.8 amp OEM charger, USB-C to USB-C, I get the "rapidly charging" message and it charged to full in around 2 hours, which is the same speed as when I got it out of the box.
However, since the replacement, my phone *almost* cannot charge with the USB-A cord. When plugged into my power bank, it will simply hover at it's current level if I'm using it (right now, I've gone from 6% to 8% in an hour) which is not normal. If the screen is off, it still takes 4-6 hours for a full charge, even when the starting point is 15%. Using the wall charger, it's the same speed with use, and without use it's 3-5 hours. I've used two USB-C to USB-A cords, one of which is the OEM cord.
I've checked OEM A cord for damages or dirt, there is none, and the other A cord is brand new, rated to 3 amps. My question/fear is, have I destroyed my battery's ability to change normally with any current under 3.8 amps? If that's the case, is there a way I can retrain the lithium ion battery to accept a charge easier? Multiple sessions of 20% to 80% and back again or something? Fully drain and fully charge it multiple times? Simply keep using it as normal and wait for it to "heal" it's ability to accept a charge over time?