This is actually a very good antiseptic and exactly, you put it in there, in urethra. This is similar to chlorhexidine.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8451623/
Miramistin is quite popular in Europe. Many providers and mongers use it right after the session as a precaution measure. It will not protect 100%, it is not a cure, but a solid post deed sanitation. I don't think they sell this brand over the counter here in the US in the pharmacies.