I have similarly stopped using antioxidants (and BTB except for a recent revisit as posted above,) and without SMB to contend with, I can usually just carbon filter instead of RO. Nice side benefit. But that might not be germaine to this topic:
Don't forget, the association of gallotannin with low oxygen brewing techniques is purely incidental and restricted to a particular approach popular among homebrewers. None of these substances or methods are used in German low oxygen brewhouses, while gallotannin has a long history in brewing outside of Germany. It was once used as a kettle fining, but that practice was long ago abandoned in flavor of more effective agents. It is still commonly used in the aging tank to bind and help precipitate proteins, enhancing the effectiveness of other clarifiers and filtration. There it also chelates metals accumulated in the process to that point. In an MBAA podcast, Joe F. said that this (just prior to filtration and packaging) is the way to go if you are using it either for clarification or to chelate metals to forestall oxidative staling in packaged beer; he was doubtful that its addition anywhere on the hot side would have any significant effect in these regards, but acknowledged that some people (mainly homebrewers) who lack the ability to incorporate the standard cold side processes might try it in the mash and evaluate it for themselves.
So go ahead and try any of this stuff. Then yeah, if you can't tell the difference, don't bother! And if it helps, do tell.