Why does my MacBook only charge when I push the USB-C plug in hard?

Please stop forcing it in. Pressure can make a damaged connector worse, and a plug that only works at a particular angle often points to debris, a worn port, or damage inside the connection.

With the computer shut down, look into the port under a light. If you see lint, don’t scrape it with metal or pour anything into the opening. If the port looks clear, or cleaning doesn’t change things, have a repair shop inspect it rather than trying to hold the cable in place.

One last useful check is a cable and power adapter that are both known to work with this computer, not just with another device. USB-C charging depends on the adapter and cable as well as the connector, so that helps narrow things down.

But since you’ve already tried multiple chargers and the connection still needs pressure, the port is the stronger suspect. A technician can check whether the port itself is damaged or whether the fault is elsewhere in the charging hardware.

Back up anything you care about while it still powers on. If the battery is already having trouble, I’d get an estimate for the charging fault and the battery together, then compare that with the cost of replacing the computer. Don’t keep charging it by bending or wedging the cable.