We have one girl all surrounded by boys and would loveeeee one more princess to complete out family any tips please!!!!!

So from what I read to conceive a girl you need to have sex up until you get + ovulation test or until your ovulation day!

And to conceive a boy you need to have sex as close as possible to ovulation day and from ovulation day and on because boys sperm swim faster and die fast as well but girls sperm swim slower but leave longer and I know this is just a theory but wonder if it really works 🤔