The only 4 year ED visa you're getting without having issues is from a university. I am 1000% sure you will have major problems at any and all airports in thailand if they see 4 consecutive or even spaced out ED visas from anywhere but a university in the system or in your passport.
regardless of what visa you have, non-b, Non-O, non-OA, non-ED and even the new DTV. If you are in the country for more than 90 consecutive days you need to do a 90 day report.
student visa are under major scrutiny due to abuse of the system, you will likely have problems in the future when entering the country or if/when you apply for a more longterm visa, if you have any type of ED visa in the system that is not from a university.
they do give a damn they however cannot legally give out more than 3 months of prescriptions though as the system will not allow it, also last I checked doctors don't make laws and legislation, so why you are blaming them is beyond me 🤦
Not going to get through customs, even with tea money. If someone I know couldn't get a couple of inhalers through, or a different person I know couldn't get 1 month of blood thinners through customs it's extremely unlikely you are going to get 3 months worth of pill through.
Try Medisafe, it will probably still be "expensive" but around half the price of what you're being quoted in my experience.