The dsa laptop spec is i5 processor, 8GB RAM 500gb hard drive
Dsa won’t cover the higher spec required for your course only what is essential to access the assistive technology recommended.
This may be the spec above, or lower, depending on what software they recommend during your assessment.
With a dyslexic learning profile you may find text to speech software like Clark read or read&write software useful. Or a dictation tool like dragon or talk type
If they recommend a laptop it will be valued around £400, you pay £200. However you can upgrade to the spec you need for your course.
Ref tablets- these can be difficult to get approved - but worth asking your assessor about