The 2020 event was not played due to the suspension of play due to COVID-19, and with few tournaments played in 2020 in many sections, qualifications for the 2021 event were a bit different, some player's who qualified for the 2020 event were given invitations to this year's event, but the 2021 event is on and in fact being played this weekend.
The 18 & Over singles event is being played in Arizona and the 50 & Over singles players are in Orlando. Next weekend, the 18 & Over doubles are in Arizona and 50 & Over doubles will be in San Diego.
The links I gave above are to the new Serve Tennis (Play Tennis) site, which was launched for 2021, but interestingly the draws are not found there and instead are found on TennisLink. The USTA appears to be continuing to have challenges with the new site, they even sent an e-mail out a month or two ago apologizing for all the snafus, and they still aren't out of the woods it appears.
I've heard rumblings about lots of issues and TennisLink having to be resuscitated, but elected not to pile on and write about them all, but it appears even NTRP Nationals, an event I would have thought would have been a key use case for the requirements for the new site, has had to resort to using TennisLink for draws.
Never the less, good luck to all the players competing the next two weekends!