Just wanted to share my experience of the Oath Ceremony during Covid as I know everyone's is a bit different and it's nice to know.
My ceremony was scheduled for 8:30am in St Louis, I arrived at about 8.15 - the letter specifically stated not to arrive more than 30 minutes prior, I had planned to arrive earlier but due to bad roads from snow and ice it took a little while to get downtown.
Walked in where security asked covid questions, took temperatures and went through security, was told about 5 times to keep masks on.
Directed down the hall where we were checked in, any family/guests were sent to wait in the cafeteria as only participants were allowed in (this was also on the letter but some people still tried)
There were 10 numbered seats spread out through the room, we were sent to our number and given a packet of information, passport application, mini flag etc.
Our USCIS rep was late due to weather but we all started checking in at about 8.45, just going over the form on the back of our appointment letter, giving in old green cards and confirming our information on the citizenship certificate was correct.
Once that was done the judge stood up, introduced himself, apologized profusely it wasn't a bigger deal as they normally had speakers, music etc.
Then went into formalities, we stood and took the oath, then the pledge of allegiance, the other USCIS rep congratulated us all, and passed out our certificates and sent us on our way as the next group of 10 was waiting to come in.
It all took just under an hour, was very relaxed and easy.
Good luck if you're still in the process! It's long and stressful but worth it