Except for the lowest and highest octave i never lift my thumb, always slide.
I have a history with windcontrollers, Yamaha and Akai Ewi , and sliding is always the good option. Ewi has rollers, making it a easier than the Yamaha. Sylphyo is best, except for the screw , but one gets quickly used to that.
Many times i have portamento on: not to cover glitches, but rather to get a nice pitch bend up to the actual note. Making up a bit for the missing mouth controlled pitch bend. The length of the slur depends on the previous note. One can create a longer slur by quickly tapping a (much) lower octave. It is a pity not all internal sounds have portamento enabled.
I did not check yet if one can switch portamento on via midi input: would be lovely.
Sure needs practise to learn how to slide fast , but thet is part of the game
I am handy with a 3D printer (see www.BreathFlute.com) and my newly-ordered Sylphyo is working its way though La Poste France (on it's way to the U.S.) ... Alternate thumb rests might be an easy project.
I was very pleased to feel the initial response , just playing the first time: Impressive dynamic range with breath. And one can tune it to a playing style so much. When i started i used a single sound for weeks : Just a flute like thing: from pppp up.
Paramater tweaking helped me a lot by making a table : with comments of results. Later i will add sounds getting the CC right.
It is a joy and fun and serious work: but you can adapt unlike ...
When you unbox your Sylphyo, its battery might not be fully charged. Before turning it on for the first time, make sure you charge it for up to 8 hours. This ensures that the battery is not in deep discharge mode, which could prevent the instrument from functioning correctly.