Thanks a lot,
Not straightfoward, but at the end it works !
Here are my change/test.
1/ Protocol Buffers Server activation (actually, I can't remember if it was already activated :() => still KO
2/ enable debug log => nothing to notice
3/ update hyperion grabber update through playstore, I was using mayber older version from a downloaded apk => still KO
4/ try to lower the priority in android grabber to 50 (was previously default value ? 500) => still KO but new error in log saying priority should be set btw 100 and 199.
5/ change priority to 150 => stil KO
6/ change udp port at WLED to 19448 (was set at 21234 from a reddit tutorial) and bingo ! :LOL::omg::picture:
So, as I remember it's roughly my very first working setup with hyperion not NG o_O
So my setup up is now working, I gonna (save my setup !!!) and tune the calibration.
Thnaks again