The beam will provide a visual partition/ a logical break point.
The eye and mind can accept a differant texture once you have that partition.
If you still need the knockdown texture in the kitchen / go for it.
You will find that the painted heavy orange peel will not sand very well.
1. rough sand 60-80 grit ( to rough up surface) 20 minutes only
2. wipe to remove dust
3. prime with Freash Start
4.skim coat with 90 minute compound / sand
5. REPEAT STEP 4 until ceiling is smooth
6. apply knockdown texture if you want.
Yes, the beam is becoming an option again, but I am not against doing some hard work and doing it right. Instead of a beam, I have also considered installing a line of decorative tiles where the beam would have gone. Both of these options are secondary to re-texturing the entire kitchen ceiling, if that is what it takes (and it looks like that it probably will).