Keys to Accessible Web Typography:
1. base font size in relative units
2. colour & contrast
3. Legible fonts with "Milimeter" test (I also use the a1iIlL0o test)
4. paragraphs shapes, line length and line height
5. semantics & heading levels for hiearchy
https://betterwebtype.com/articles/2019/06/16/5-keys-to-accessible-web-typography/