Vertical mouse movement makes certain glides much easier to perform but there is no current in-game hotkey to toggle it.
It's possible to use scripts or mouse software to avoid this issue.

Is the use of these third party tools allowed?

If not, is one allowed to enable it via the "customize control" menu in the middle of a run and than disable it? (This would take seconds but certain glides save minutes in a run).

The reason it works is because of the jank vertical mouse movement that Unity has. Go into your key bindings and change move right to mouse right (up for some maps with glides), then just make your way there with the super jank mouse movement and use jank vmm to build momentum off the wall and you'll make the jump. Angle also matters, so if you keep failing, it's probably because your angle is off due to Unity being...Unity.

Known bug in Doom's code. This is why we have a separate category for nightmare full game runs with saves and without.

Doom (Unity Ports)

Nightmare! saves and pinky demons' speed bug