Though there is still a two-year wait until Shazam! Fury of the Gods, director David F. Sandberg is already teasing a bigger scope for the sequel that shall outmatch the predecessor film released in 2019.
Since Fury of the Gods will release after The Flash, the latter could factor somehow in the Shazam! sequel in some manner.
Regardless of its deeper connection to DCEU, the film does promise a bigger scope as David Sandberg has promised.
Shazam! Fury of the Gods will release on June 2, 2023, as the fourteenth installment of DC Extended Universe.