When using a controller via MidnightControls, Disable Flying Momentum limits creative flying speed to the same, if not slower than, sneaking on the ground. Tweaking MidnightControls joystick settings warranted no change. WASD works fine, however.

Turns out Motschen had a mod out called MidnightControlsExtra that toggles flight drifting that doesn't conflict with Bedrockify.

https://modrinth.com/mod/midnightcontrols-extra

Closing this issue.