Some screenshots from Scooby-Doo and Krypto Too! have been posted on the Digital eMation Inc. homepage! The site shows that Scooby-Doo Meets Krypto (note the different title) was in production in 2021. Some characters including The Joker, Harley Quinn, Superman, and it appears many others as well. The villain appears to be Solomon Grundy, and he appears in both screenshots. Given this info, I'm really hopeful we'll still get this film!
Thanks to Scoobylover for finding this info!