Oxygen

So I haven't played Subnautica much over the few years I've had it, and wanted to ask for advice on conserving oxygen particularly for cave diving and wreck exploration. I learnt recently that I can carry multiple O2 tanks, so I've been carrying two hi-cap tanks and am working on a third, but wanted to know if it's worth using bladderfish as O2 reserves. I also have trouble because I'm trying to access the degasi shroom base, and I can only switch to my rebreather after I'm in the caves away from the radiation, and if I die in the caves I start to take radiation damage when I respawn at my base since it got irradiated after the Aurora exploded. Can anyone suggest the best way to keep my oxygen up and replenish it without having to escape the caves and return to the surface? Are floating pumps worth it? or should I just park a seamoth at the edge of the depth limit and use it to replenish O2? Maybe an I compartment with a hatch and solar panel? Would the panel receive sunlight in the vertical hole that leads to the caves, since it's got line of sight, or is the depth too much for a solar panel, and will I need a multipurpose room with another power source?

I am in the dgr degasi base and I’m low on oxygen and a crabsquid is camping the exit

All of the oxygen in seabases, vehicles, and oxygen tanks, are made by the oxygen generators, and the oxygen in Precursor bases is presumably separated from the water in the PCF and pumped across the planet, not natural or pumped from the surface or anything like that.

Later in the game, like from the time you enter the Lost River to the time you disable the QEP, your character probably doesn't breathe any natural oxygen whatsoever.

Everyone go back to the surface, give Ryley some fresh air.

So where should I go first. I also should probably mention that I have no vehicles, only a seaglide. I SWEAR TO GOD, IF SOMEONE SAYS VOID I WILL LOSE IT