I know this is a late response but.. if you're wondering about player NBT data then always remember the /data command. So: /data get entity @p. This will show you the Air NBT property which has a default value of 300s.

Unfortunately you can use /data to affect blocks and entities but you cannot do this for players, you'd need specific commands to do that. Comparable to /data get @p Inventory. I can check a players inventory this way, but I cannot modify it; I'd need the /replaceitem command for that. Same applies to the Air property. But unfortunately there is no command for this..

Um no i think maybe you need a mod? i know there is a mod that you can make you not die at all from water though

The only way I could think of is to lower they’re health via /effect name instant_damage

I don't know exactly how to structure the command but minecraft should help auto compleat the comand

/attribute @a air (I think that 20 is normal)

This command reduces or increases the bubbles you have when you go swimming but the /attribute command is a 1.16 command.

I hope this helped

If it can accept data packs I might be able to look into making one like that, wanted to make one for more time underwater anyway so might as well make the reverse too haha, if so lemme know what version you’re on I like a challenge

This may be possible with the help of a plugin that edits these values, but I don't think it's able to be done completely in vanilla. I would see if you can find someone who's able to write a plugin like this (if it's possible). It might also be able to be done with a datapack, but I'm unfamiliar with those.