Is it obligatory to perform ghusl and repeat the prayers after seeing a slight reddish discharge with a little blood, as if it were transparent secretions with a reddish tinge, more than a week or two before the menstrual period, knowing that ghusl was not performed completely and only wudu was done at that time?

The authoritative view we adopt is that brownish discharge, if it is separate from menstruation and not accompanied by its known signs, is not considered menstruation. However, it is impure and invalidates ablution (wudu'). Therefore, there is no need for you to repeat the prayer if you purified yourself from it and performed ablution for the prayer.