Your new shoes will take a wee while to bed in .
Initially the stopping will be terrible , but as the shoes make contact
over the entire surface , it will improve .
Been through that with my DT1 , and now it brakes pretty well .
When I originally fitted new shoes , nothing much happened when
applying the front brake .
If you've been spoiled with modern disc brakes , it won't ever match them .

They ideally need an adjuster at the bottom end as well as at the handlebar lever. It's a bit much to ask the lever adjuster to take care of all of it. Can only set the arm at the cam as best you can then take it up at the lever. I have in the past threaded the lower cable mount then fitted an 8mm adjuster but needs slotting or otherwise un-soldering one end nipple to slide it on.

Re-thinking--wake up 'me'-- i think i used a lever adjuster as is slotted.

One thing I found when working with a brake cable that only adjusts at the top is to unbolt the hand lever at the pivot instead of hooking the cable to the lever and trying to stretch the cable over into the adjuster. you get rid of way more of the slack and will be able to set the bottom arm right where it needs to be,  If you're not already trying it this way, this could solve your adjustment problems