You need to still have one platform in here. You should be holding two platforms when falling into the room on your left - one goes to the switch, the other is used here.
Well, you can just put the platform on the switch and walk through.
Which will give you a preview of this section.
The actual puzzle is to get to this place with two platforms, put one on the switch and walk through the gate with the other. A lot of the rooms before this one tried to take away your extra platform - so trace back and see where you lost one that you didn’t need to lose.
Oh, I am definitely OK with that.
You can see the “intended” solutions here (but it’s kinda a spoiler): https://youtu.be/Bn0o1hITR1A?si=te0XmEqcKFnEErm2&t=682
However, there are some more efficient ways of doing these things.
Alternatively, if you want to just learn the ideas of “platform resource management”, go back to the Anti-Hub and try to solve The Butterfly Effect (which is the middle exit from there). Once you can solve that one, you probably should be able to solve the ending.