Are these secretions considered "madhy" (pre-seminal fluid), and should one follow the Maliki school of thought, performing ablution and praying more than one obligatory prayer with the same ablution, or what should one do?

You must ignore obsessive thoughts and not pay attention to them. Ablution (Wudu') is valid unless there is certainty of the exit of nullifying discharges. If discharges exit with certainty after lust-inducing thoughts, they are likely madhy (pre-seminal fluid), which is impure and nullifies ablution. The default is the validity of ablution, and it is not nullified except by certainty, according to the Prophet, peace and blessings be upon him: "He should not leave (his prayer) until he hears a sound or perceives a smell." Whoever experiences continuous vaginal discharges should perform ablution for each prayer after its time has begun. It is permissible for those who find it difficult to perform ablution for every prayer to follow the Maliki school of thought in this regard.