https://www.ukm.my/fsk/klinik-psikologi-kesihatan-2/
before you go, you need a GP to refer, which you can get from any clinic.
It's quite a thorough examination, around 3-4 hours.
for full paying patients (approx Rm1k) the appointment can be had within a month.
If referral with OKU card definitely cheaper but waiting can be up to 1 year.

I'd do low hanging fruit stuff first, if you haven't. Such as, hearing and eyesight test. Also can consider doing an assessment at https://dyslexiamalaysia.org/