Any mechanical detectives able to help me figure out what might be wrong with my beloved 91’ isuzu trooper rs😔

Check engine light turned on when i drove it on the freeway if i was using the gas Would then turn off when i let off the gas (always did this didnt think much of it) Had to stop driving it because of the issue im concerned about now Went to drive it one morning and it started idling really weird "Chugging" in first gear once i went fast enough it kinda would stop But it felt like at any moment the battery would give out if i wasn't actively in motion

Today (three months later) i tried to start her up Needed one hell of a jump and once it was on i went to drive it to get the alternator going hopefully keeping the battery running

The battery may need replacing but autozone claims i need to bring my car with the battery to get my one year warranty honored (its wont make it there)

Started doing the chugging thing again and smoking ?! (Refer to link in comments to see the videos)

Can anyone give me any advice or rather any ideas what could be causing this🥲