I thought it was bacteria that caused the oxygenation event. Was it plants?

Oxygen is extremely toxic. Both to humans and especially anaerobic life forms. Having the biochemistry to deal with low concentration of oxygen doesn't really mean much — it's like saying mercury isn't toxic if you have the biochemistry to deal with it.

Meh, complex life as far as we can tell is because of oxygen. If there are aliens out there, they're most likely susceptible to oxygen toxicity but they're also brainless anaerobic single-cellular life forms.

It really is as far as we can tell. It's much more likely that anaerobic (glucose based, not oxygen) life exists than aerobic. Many reasons for this include it's easier (doesn't require a ton of oxygen), less dangerous environments (not exposed to open-air), and as far as we know is the precursor to aerobic life. Anaerobic organisms, before anti-bacterials, were extremely successful little survivors :)

Not necessarily, oxygen is considered extremely toxic for life. Our very niche form of life is aerobic.

Lmfao. NFTs, which are made to allegedly prove ownership, needs ownership protection. That's rich.