There are 4 things that can be wrong with dell that is not charging :
-Damaged charger , data pin i broken (pin inside the charging plug) , cable is broken so it doesnt transmit power/data
-Charging port is broken
-Motherboard electronics is broken
-Battery is dead
Easiest way to check what is wrong ?
Get any known working dell charger(can be with lesser or bigger W) plug it in to your laptop and check in bios is it recognizable .
If ur laptop did not recognized charger it might be issue with charging port or motherboard , ofc first replace charging port
If charger is recognized it can charge ur laptop when it is off even with lesser W than it is recommended for ur laptop but will cause hard throttling during using of laptop
I was dell HelpDesk specialist for 4 years i know what im talking about