×With help of gel babies I've blocked 16,4-21,4 from gel while it growed to the pressure plate

×A pressure plate won't activate if there's something already on it when you step on it.

Only two of the things in this room can hold a plate down indefinitely: gel from the gel mother, and rubble from the golems.

Since you can't lead golems out from the left side, this means you'll need to use gel for at least one plate. Note that it's only necessary to hold down one plate on each side, though you also need to make sure you have a space to stand on yourself.

×I don't think you understood my last hint.

First, a clarification: when I said "each side", I meant "east and west" not "north and south".

But you don't seem to have understood the basic idea I was trying to explain; when something is on a plate, that specific plate is held down. Which means anything else moving on or off the plate will have no effect on it.

Holding down a plate on the east side won't have any effect on a plate on the west side. You have to get some gel on a plate on the west side, then step on the same plate without disturbing the gel.

In particular, this means you can't have more than two of the plate's tiles covered with gel.