Mi A2 Lite No signs of life after changing the battery

Hi, I have an old Mi A2 Lite with charging issues. It fell in the water some time ago, I successfully retrieved it and went on using it for some time, only issue was the battery draining faster (about half the time). Then I changed phone, let the A2 in a drawer and the battery drained.

Some days ago I tried charging it again but all I got was a blinking led, nothing more. Ordered a spare battery and changed it, then tried charging. LED was blinking irregularly as if the power supply was inconsistent (cable is ok), s reopened the mobile to check the charging port. Then, no more signs of life. Checked many times everything, but still nothing when I plug the cable on.

I don't really need the phone, I only thought it might be handy to have a spare on ein case my other has issues (like a broken lcd). And, I'm trying to make it working for the sake of learning. By the way, I'm not sure it is worth buying expensive parts. Is there anything I can check before I abandon all hope?