I think my charging port is loose or bad or dirty.

@adamtomesh since cleaning does not resolve the issue, I would suggest to replace the charging board. Those boards are widely available and luckily not to costly. Just remember that you will need one that is for your exact model. Check on sites like this for an idea of what you are looking at. This is not an endorsement of the seller, just an example. To replace it, use something like this guide It is in French but browsers like Google Chrome translate these almost perfectly.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

I had this exact same issue on my S23 Ultra, with USB Charging and Android Auto disconnecting so often both were unusable. Cleaning didn't fix it, and I called Samsung to figure out what to do.

They suggested to wipe the cache partition.

I scoffed at the idea, since the issues I was seeing seemed like an obvious hardware issue, but tried it anyway. Much to my chagrin it actually worked, and I haven't had any issues with USB charging or Android Auto disconnects for months now.

To do it, shut down your phone. Then hold Power + Volume Up until it brings up the Android Recovery menu. Use the volume keys to go down to Wipe Cache Partition, then press power to select it. You'll still have all your apps, data, etc and it's a whole lot faster and cheaper than trying to replace boards or send it back for a replacement.