I have found a similar quote, Anno's own words in Shin Ultraman Design Works:
This is interesting project. I had no idea Anno had any ideas to expand on Shin Godzilla but I am specifically surprised he still considered bringing in additional monsters and aping the Champion festival films. Shin was such a different take it's weird to imagine taking it a more conventional turn.I wrote a proposal during the filming of Shin Godzilla on February 3, 2016, labeled Sequel Shin Godzilla Memo. The primary working title for the project was Shin Godzilla's Counterattack (シン・ゴジラの反撃, Shin Gojira no Hangeki) and with the assumption that Mr. Higuchi would direct, it was meant to be something like a Toho Champion Festival kaiju showdown. Since it was concocted to be released in 2018, the shortest time possible for a domestic-made Godzilla film to be released, it was a rough draft for people who wouldn't like Shin Godzilla, an idea that wouldn't cost too much or take too long to create. I believed that it would be a bad idea to let it go to waste so I gave the proposal, draft, and visuals, as a gift to Mr. Higuchi and Toho, but since it was premature or whatever, among other reasons, after the film's release the discussion ended. While I did feel it was a waste, it's not something I could help since Toho decides what gets made.