People forget that 'mask' in the UK means face covering. You can literally just cut up an old T-shirt, put it over your face, and call that a mask. Last week I saw someone on the tube with what looked like a silky cocktail dress material shaped into a mask, one layer. That's NOT a mask.
Last time I was there (early summer), France insisted on medical-grade masks. Which have been proven to be at least somewhat more effective than just any piece of material people like to call masks.
In Germany where I live, FFP2 masks are mandatory. You can't use public transport or go into a shop unless you're wearing FFP2 (in my state at least). Why? Because they're actually effective. Children under 12 can use a medical one (the blue disposable ones, although they're now in all colours). They slightly relaxed the requirement last month and for some indoor spaces (like museums) you can now use medical instead of FFP2.
You are also challenged by the security staff at the door or inside the supermarket, you get fined on the train if not wearing your FFP2 properly. You cannot declare yourself exempt - you need to carry a doctor's certificate and even then, businesses have the right to refuse entry to those unmasked, whatever the reason (I don't fully agree with this btw).
If you're going to make masks mandatory, use those that have the greatest effectivity and also protect the wearer. Ever since FFP2 became compulsory, the rates have remained steady-ish and are lower than ever - and it was nothing to do with vaccination as this happened back in February, and in the middle of a winter wave, when something like 5% had been jabbed.