Based on that, I’d say the most reliable choice would probably be replacing the USB-C board. While USB-A supported punching/expanding the cables themselves to stay better in wide/loose slots, I don’t believe that there’s any standard or safe way to do that for USB-C cords.
Another possible option would be trying to utilize a wireless charging puck which would be pinched into the slot through the case, which I’ve previously done, but that’s not a great option if you often connect it to a computer. Regardless, it might be an easy workaround if you’re not feeling like trying to replace a system board, and it can be a nice feature as well. The one I purchased 3 years ago has the Type-C out of stock, but here’s another one that ships for a few bucks delivered:
New Wireless Charger Receiver For Samsung Huawei Android Type-C Micro USB 1/2 | eBay
As well, if you don’t have any, you’d need to get a wireless charger. The portable pads work well whether with external batteries or attached to your charging areas, though they don’t keep your phone fixed in place if your phone is on an unstable surface such as a bed. Regardless, it’s a decent spot to start. Here’s an option as the one I’d picked up years ago has long since had its listing expire:
Wireless Fast Charger Charging Pad Dock for Samsung iPhone Android Cell Phone | eBay
Remove the case, plug in the connector, put the receiver against the back of the phone, reattach the case, and then put the phone on the (plugged-in) charging pad. If all goes well, the phone should show that it’s charging normally. With that charging dock, it should light up when your connection is good and turn off when it’s not lined up properly.
Anyways, replacing the bad port will be your best long-term option, but it’s also nice to have options and I’ve enjoyed both my wireless charging era and my current magnetic USB era. 
