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I learned all the notes on the fretboard by using them like counting sheep to relax and go [back] to sleep.
I started at the head stock from 6th to 1st string. At first I recalled only major scale frets (2nd, 4th, 5th, 7th, 9th, 11th, 12th). Later after those were comfortable I added those in between.
Then later I began to mentally do all 7 notes singly all over the fretboard (starting with a root (say A, then the 3rd, C, then the 5th, E). Then use the fifth, E to act as the new root… then 3rd, G… then 5th, B. Etc. Etc. I not only learned the notes that way but the chordal relationships and the Nashville numbering system. I never did it as a learning session or with the guitar. I just did it mentally as a prelude to rest or when I was doing a repetitive task like weeding. In about a month or two I had the fretboard memorized and never felt like it was real work.
Kudos to you for sharing your tuner learning tool idea.