What should typical semi-quant tot antibody levels for covid spike be after infection (unvaccinated)? i had about 3300 u/ml in feb 2022, 568 in jul 2022, and 378 in may 2023 with no verified reinfection. is this clinically significant?

It appears that your antibody levels are decreasing over time which means you have not had another infection with COVID since Feb 2022 (or prior to that). These antibodies decreasing mean that you will no longer be protected against infection if an exposure happens. It would be recommended that you get a vaccine, if at all possible, to protect you from re-infection, Good luck!!