here are my two masks not diy
https://www.amazon.com/3M-Respirator-6100-Respiratory-Protection/dp/B007JZ1NIM
and the mother of all masks
https://www.amazon.com/gp/product/B002MFGE92/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
No need to improve on these. Replacement filters are about 20 bucks.
Funny but both of these masks protect me not you. my doctors office prohibits me from wearing a mask that protects me.
I’ve got one like your first link. I use it as a dust mask. I also have a mask for spray painting that has the charcoal loaded cartridges. I don’t have a covid mask. Wore one once last year for all of 10 minutes.
A surgeon’s mask like the cheap blue things everyone’s using, is meant to keep the surgeon’s spittle out of your opened up body, nothing more.