What they mean is:
No one uses physics in unreal to begin with (because chaos sucks). Pretending to simulate physics and obtain the same result from different scenarios is just outlandish, for pretty much any engine.
Best you can do is “not use physics”, which is the first answer you were given.
The next best option is “hope”. Basically, you hope that applying the same value to the sameobject at the exact same moment in game gime will produce similar results with as little margin of error as possible: good luck.
Your only option to have something that seems like physics would be to make it so that only the server does calculations and serves positions out to the clients.
Obviously, on simulated objects, even over a t1 line, this is not only impractical, but next to impossible to achieve with any smoothness due to network lag.
What AAA games do, is to allow the client to simulate (hoping it is somewhat accurate), then lerp or warp the object to the server given location.
When done correctly, the player won’t notice.
(Granted, the avarage player wont notice the room caving in under them, so you have a fairly low bar to reach ;p)