Seems like they were damned either way. They spend a ton and the films underperform, it’s their fault. If they take a strict stance on the budget, and Snyder would say that they didn’t support his vision.
Possibility exists that Snyder simply wasn’t the right person to lead DC, on the big screen.
The point is even if he wasn't the right person, they still carry responsibility. They hired him, they gave him carte blanche, they let him film an entire movie even after they already didn't believe in him anymore and their plan of 'fixing' his movie in post was always insane on the face of it. And then they rushed the movie out with bad cgi to pad their wallets with bonuses.
And it's also not at all wrong to say that plenty of bad decisions continued to be made for the last 5 years of the DCEU after Snyder was already gone.