Should I switch 10% minoxidil to 5%?

It is best to discuss medication changes with your doctor.  In general the normal dose of topical minoxidil is 5% applied twice a day.

It can take 6-8 months to see improvement with Minoxidil. I suggest seeing a hair loss expert to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like PRP/progesterone which work well in combination with Minoxidil. See an expert. Best, Dr. Emer

If 10% did not work, then 5% won't work either. After a 5 month trial, it is likely that Minoxidil is of no benefit to you. Hopefully you will have better results from the Propecia. If after 4 months that does not work, you have two options left:  LLLT and PRP. If these fail, then your only option is a hair transplant.