My charger isn't connecting to the phone

Does it do the same thing with a different cord? Assuming that's the case, have you cleaned the charging port? Over time, especially if you carry your phone in a pocket, dust and lint can collect inside the port and clog it up, keeping the cord from being able to plug in fully.

So the first thing to do is clean the port. Get yourself a magnifying glass and a bright light and look inside the port. Clean it out with some 90% or higher concentration isopropyl (rubbing) alcohol, maybe some toothpicks and eyeglass cloth. Don't use anything made of metal inside the port unless you disconnect the battery first. Once it's clean, check the pins carefully, looking for bent, broken or missing pins. If everything looks good, try plugging in the charger and see if it works better.

If not or you find issues with the pins, then the only solution is to replace the port. You're fortunate in that on your phone the charging port is mounted on an easily-replaceable flex cable rather than on the motherboard like a lot of phones. That means the replacement is both reasonably simple and fairly inexpensive. Sorry to say, iFixit doesn't have a guide for your phone, but I located one on the Spanish site Nadie Me Llama Gallina. As you might reasonably guess, the site is in Spanish, but it does offer English language translations if needed. Using it with the Chrome browser's translation helps, as their translation feature isn't complete.

Manuales / OnePlus 11 / Flex de carga - Nadie Me Llama Gallina

Be sure to come back and let us know what you found and what fixed your problem to help the next person who comes along with the same issue.