Finally i reply to myself, aving found some workaround ( as often in blender 
) for it’s usability & for my workflow.
As i said, what i needed in 3D view are those modes:
- wireframe ( not very often )
- solid for 3D navigation/edition
- textured ( simply for fast rendering ) for UV edition & immediate visual result control
- rendered ( not often at all )
my solution came from shortcuts !
I used Z for switching between wireframe & solid
—> 2.9 key shortcuts
and I used Page UP for switching between solid & textured
—> 2.9: the art of keyboard shortcuts
This way my workflow is just perfect, like it was on 2.79 ! and i don’t get bored or overwhelmed with menus, options and other useless ( to me ) things…
At last but not least, i reinstalled with ease the Magic UV addon ( that works fine in 2.9 ). Now i only have the command recorder addon to check 
Honestly and for my particular use of blender, except for rendering and fireflies handling wich is much better in 2.9 than in 2.79, i now feel no noticeable difference between 2.9 and 2.79.
Except maybe on performance for million triangles meshes in edit mode…
If you feel some things that were better in 2.79 and in 2.9, just write here and if i can help you do the jump, i’ll be happy 
Happy blending !