A similar thing to what you described happened at a software company where I used to work at, culture destroyed, many people let go. I will name and shame the PE firm - it was Hg Capital
However currently, I've been at a company for a few years who is owned by Morgan Stanley Capital Partners, and it's a completely different story. The culture is great and hasn't changed at all
Bought by a growth equity fund? Probably fine. Bought as part of a roll up? Probably screwed.
PE is like tech: similar tools, but very different firms.
They bought us not for our technology but our customer base. They intended to convert them all to their other firm's product. Little did they know that a lot of our customers had left the other firm for us because we treated them better.. So what happened is in addition to the back office staff & sales staff being laid off, they laid off the developers & testers too (they kept a few managers for a year for continuity). I realized this when the folks they sent to town refused to go to lunch with us in an rather awkward moment.
Always appreciated and very helpful. Nothing in this comments suggest that it deserves any downvotes.