"No feedback brakes" go from nothing to full lock

Kinda what I was getting at with the “all 4 wheels or not” thing.

OP says both the master cylinder and the booster were replaced with no change. Obviously it’s not impossible that both boosters are bad, but I would think that’s unlikely. If the master cylinder diameter stayed the same that could definitely be the problem, but, only if the bore diameter is the wrong size.

And if there’s a vacuum issue somewhere else that could be it as well, and wouldn’t have changed with the parts that were replaced.

But without more details from the OP we’re all shooting in the dark.