I did just look through a stack of around 200 bills, containing 1s, 5s, 10s and 20s, and indeed didn't see anything past 2017A series. Forgot about how Mnuchin did his "signature"... hilarious. Kids can't read cursive these days anymore anyway!

Mint has certainly put new coins into circulation since 2017. Have plenty of quarters and nickels since, including the new designs to both, and special edition Washington crossing the Delaware ones with the Trump like GW face...

It would seem that bills were at least ordered to be printed though... you suggesting they weren't printed, or at least whatever was printed wasn't put into general circulation?

https://www.federalreserve.gov/paymentsystems/coin_currency_orders.htm

Edit: I think I get it now. It's not that no new bills have been printed, but rather that no new series have been authorized since 2017. That is indeed somewhat odd considering that historically new series would come out every 2 to 3, maybe 4 years max, seemingly around starts of new presidential administrations or changes in Sec of Treasury.

https://en.m.wikipedia.org/wiki/Series_(United_States_currency)

The implication here seems to be that the current Sec of Treasury, or at least is claimed to be the legitimate Sec of Treasury, is not legitimate and thus cannot issue any new notes...