Cuphead - Beppi The Clown Post Patch Phase Freeze Glitch - Speedrun Strategy
So you can still get the Beppi freeze (fairly) easily if you use Charge. It's very easy to replicate, but you need good RNG so Beppi does not use his quickest attack pattern and you need to get a parry to have enough cards to do it.
In the first two attacks, make sure you do exactly 5 fully-powered Charge shots and 3 regular Charge shots. This puts Beppi on the cusp of his phase change.
Immediately after Beppi hits the wall and turns around the second time, hit him with Charge Shot/Charge EX as much as you can. It takes 5 fully-powered Charge shots and 4 Charge EX shots to get the freeze. Keep in mind that Beppi's hitbox is still present for a short period of time after he falls off into the background.
If you use Whetstone, it's even easier since you can parry him while shooting him.