I've been using this tool since SIMANDL 2 has tenor clef exercises in it:I can read music - like a kindergartner reads words, painfully and slowly.
I know that if I put even 10 minutes a day into systematically improving my reading, I'd get better.
What do you recommend for learning/improving reading?
https://www.notationtraining.com/tenor-clef-practice
One can also change the reader to bass, treble, and alto. There are even treble clef chord exercises.
Plus, it times one's efficiency on each exercise.