health insurance concerns? established stable chronic illness - is it worth applying at all?

Hello! <3

Is there way to check/research how strict the exclusion for pre-existing conditions is for the programs health insurance? I saw posts there can be delay in its 'start' after arriving. I have monthly prescriptions that can't be skipped for longer than a few days. Depending on my leave date, I'd probably be able to get 1-3 month fills from my US doctor to travel with in the event there was a 'delay'.

I'm very used to dealing with the beaucratic paperwork / scheduling stress system of things - so my concern is the 'pre-existing' conditions meaning I would need additional private insurance for monthly prescriptions? Or that a doctor abroad would 'disagree' with mine back home and refuse to fill the same medicines (I've checked that they are all available in Spain already).

I'm 'between' leases and living with my mom so I'm able to save up pretty well. But if the costs of private insurance in Spain and medicine is equal to or more expensive than US it doesn't seem worth applying?

*specific price of medication I'm worried about is migraine injection ajovy, emgality aimovig