Thanks to bender007 and to bajangg for their explanations in the forum, I succeded in downgrading my EMUI.
The most difficult was to downgrade, because I usually use a Mac, or a proxy connection... When I succeeded in downloading HiSuite 11 and 10, I was out of trouble. Just had to be patient.
Huawei P40 Pro
Model ELS-NX9
Build 11.0.0.151 (C432E3R5P3)
1/ with HiSuite 11 from EMUI 11 to EMUI 10.0.1.176
2/ with HiSuite 10 from EMUI 10.0.1.176 to .131
3/ Googlefier didn't work... In fact it worked but I kept having the annoying notification asking for Play protect....
After 10 attemps to fix the problem, I tried somthing else.
4/ I downgraded form 10.0.1.131 to 10.0.1.109 with HiSuite, then started again with Googlefier.
After 3 or 4 attemps it worked.
Now I have everything running good, Playstore, GMS, G Maps, etc...
I updated everything and now I run EMUI 11.0.0.168 with Play store ok.
I'mposting this RETEX on the forum for everybody to understand that's just a question of following the method and not waiting for it to work the first time.
Thank you very much Bender007 or Bajangg for the time you spent for all of us.
Please take some time to read everything they wrote, and to watch to the videos (specially the one bajangg posted about downgrading).
And take a minute to donate...