Go into setup (F2 at powerup) and verify the AC adapter is recognized (i.e., power rating shows -- not "unknown").  If it doesn't, try another OEM Dell adapter.  If it too is showing unknown, replace the DC power jack:

https://www.amazon.com/Socket-Harness-Precision-064TM0-DC30100X300/dp/B06X15K6YG

If that doesn't get the AC adapter recognized, the charge circuit on the mainboard is blown - replace the mainboard.

If the AC adapter IS recognized, or you get it recognized as above, but the battery won't charge, the battery is dead;  replace it with a new one.