First Request: for 1.12.2
I think as soon as the player is not in a oxygen environment instead of them start taking damage straight away it should first use the oxygen like what happens when you are under water. kinda like holding your breath.
so have in the config
PlayerCanHoldBreath =1

Second Request: for 1.12.2
Ability to modify the amount of Air bubbles taken and how often such as
//Low02 oxygen settings
low02HoldBreathDamage=1
low02HoldBreathTickRate=100
These settings would consume 1 Air bubble every 100 ticks. (if modifying the air bubbles is not possible then modify damage taken)
The reason for this change is that there is oxygen on the planet while it is minimal breathing is just difficult it might kill eventually but this setting would allow a greater configuration.

I hope you consider my request.
Thankyou.

While I am open to allowing a delay before starting oxygen damage, it will not be through the vanilla bubbles. Too many mods modify those for them to be any use in our case.

You would certainly know better, a delay before taking damage would be excellent.

But if you hold your breath, the air would get sucked out of your lungs immediately, followed by a total lung rupture and collapsed lungs.