So I would like to see the location of every pokestop and gym near me on a single map with a range of 20km, but the wayfarer map needs me to zoom in so much, making it difficult to know the locations or density of pokestops and gyms near me.
So is there a way to see every location of or density of the pokestops and gyms within the stated radius?
Short answer..no
You can use wayfarer map to see wayspot, but you need to zoom. Wayfarer never ackowledge s2 cells so i dont think they will make the map big enough to see in 20km radius
IITC with various additional plug-ins and browser extensions for Pokemon Go would also work… kind of. It’s a very non-trivial thing to set up (I’m not the person to walk you through it). You’d still have to manually mark which Ingress portals are stops or gyms as well as manually add everything in the desired area that’s been added since Niantic Spatial and Wayfarer split almost a year ago.
Until recently I was doing this and had been since “before COVID”.
Best stick with the short answer above and hope that later versions of the Wayfarer map give you what you want.
The map in Campfire will show gyms (but not pokestops, Campfire doesn’t show pokestops at all) at a much more zoomed out level, though not enough to get a 20 km area all on screen at once. Once you zoom to about 4-5 km wide on screen, it starts filtering them.
You can add your thoughts about the zoom level to the main discussion post: The Wayfarer Map is HERE!
Since the Map was released being able to to see a wider area seems to have been be most suggested change.
Staff have stated that it is currently V1 and they are expecting updates in the future.
Don’t think we will ever get anywhere near 20km, at that level even mid-range populated areas would just be a jumble of stops and not much map 
I think being able to see 4 complete cells would be fine, some would be happy seeing 1 cell at once.
As a test I used one of the unofficial maps and at it’s widest I could see approx 15km but you get areas as below, and this is not you “saturated” areas…
