There's no harm in re-characterizing "just in case"...the only downside is you might do so without needing to. There's also no harm in waiting, as long as you do it early enough to complete the re-characterization before Dec 31st 2023 (the conversion back to Roth can happen any time, as long as you don't have pre-tax traditional IRA dollars in the same year - but you do pay taxes on earnings when this happens so it's best to do it ASAP after re-characterization).