I would just try auto focusing instead. The stigma against auto focus is silly if that’s why you are using manual focus. If it’s the cheap 1.8 canon 50mm then I know how short of a distance that lens has to focus. Will be near impossible to get solid stuff in-focus that quickly and you’ll just lose good photos.

I’ve never seen an AF lens with distance scales that were worth a crap. Especially if you’re trying to do it with a focus-by-wire lens that has no actual physical connection to the elements.

The classic method for street photography was zone focusing anyway, so you’d set your focus distance a certain ways out (or at hyperfocal, so everything beyond a certain line was in focus out to infinity), usually stopped down to increase the plane of focus.

For street photography a good technique is zone focusing. For example F8 on a 35mm you can pre-set your focus to 8 ft which means that everything from about 5-1/2ft to 15ft away will be in focus. No waiting for your auto-focus to catch the subject, as long as they are withing the zone, it will be in focus.

Here is a site that explains this technique in better detail

https://www.ilfordphoto.com/zone-focusing/

Turn on focus highlights or split prison or something

Get an old school manual film camera. My husband bought me an old Pentax a few years back. The way the camera focused with the view finder was really awesome. It was the coolest gift. I’m sad it ended up breaking pretty quick tho. may look into getting another one just for fun.

Practice, but also zonal focussing is your friend for street with a manual lens.