It's usually just dirty

Look into magnetic charging adapters. I'm just putting them on my wife's devices out of the box now.

Charging ports wear out if used often, which is why I usually charge wirelessly and keep a lint cap on my port.

Same, but with my laptop. 😔

1. Test the cable first if you have a spare.
2. Test the AC adapter if you have a spare.
3. If both fail, inspect the charging port with a flashlight. 4a) If it looks dirty, try cleaning it out with a toothpick (if you have a dedicated plastic tool for mobile repair, use that). 4b) If it doesn't look dirty, refer to 4a. What often happens is that lint from your pocket compacts over time as it gets in there and then gets pressed in by the charger.
4. If this doesn't work and you have a good, locally owned mobile repair shop nearby, they might look at the port for free just to see if there's anything you missed.

Only after all of this would I start to strongly consider the phone itself as the culprit.

Possibility 1 the port is full of crap, clean the port with a thin stiff piece of plastic.

Possibility 2 the port is broken, treat your equipment better.

Possibility 3 the cable is bad, replace the cable and treat your equipment better.

So, the first thing you need to do is to figure out if the problem is in your phone or in the charger. Try either charging your phone with another charger or using your charger to charge someone else's phone.

If the charger is the problem, it's most likely broken inside and you need to get a new one. Tape might do the trick for a short time.

If the phone is the problem, try cleaning out the charging port. I personally use bamboo cocktail sticks that I crush with pliers to make them have small rough bristles. Lots of objects work for this (pretty much anything thin, preferably brush-like), just as long as you don't put anything wet there.

I only ever had this problem with micro USB. Thank god we abandoned that shitty connector

I got some magnetic detachable usb cables and the end that detaches never gets unplugged from my phone. Although i mostly charge mine with a wireless pad on my nightstand.

I had a little plastic army guy go missing from my diorama. Turns out, he was in the charging port,of my phone. :)

This and also battery wear is why I charge my phone exclusively with wireless charging with all the fast charging toggles turned off.

Mine started the same thing a few weeks ago. I tried cleaning out the charging port but after a while of scrapinc I gave up since nothing was coming out and I couldn’t see any more lint in there. The problem persists. I am confident that no one in the world has it as difficult as me right now.