The tuner I use for bending training is …
Lingot 0.9.1 under linux, because of the spectral view. I love seing the frequency peak sliding in the right direction when I try to bend. It is also easy to spot the tone skip that might happen when the tongue doesn't follow the mouth cavaty. I have tried several others, this one has my preference.
What is yours ?
Pano Tuner but its the only one Ive tried
is quite good for bending training
I have tried the visual aspect of both Cleartune and Harpninja, but what worked best for me was using my ear to match my playing to a prerecorded tone from an online tone generator. If I want to practice the 3 half and whole step bends, I will use the tone generator to record those particular notes, create about a ten second loop, then repeat it in Amazing Slow Downer and match my playing to those tones.
I like this one: https://www.flutetunes.com/tuner/
It provides great visual feedback and is available everywhere without instalation.