Hi, first of all, thanks to you all for all those precious answers.
I have heard you all and I'll work on my side to understand better what I'm doing with MOSFET and the bridges themselves...
I may comeback in bit with better questions if I still have some or not but I'll close this subject as I need to work on my side to understand it all better.
Thanks Andree Henkel for the explanation about the charge pump, I understood what you meant on the spot but indeed I didn't knew that. I had some trouble with that charge pump on the drv8844 that may be the reason why I destroyed some of them as well..
Thanks brumbarchris, I will save this post for later of course !
Thanks H.O for the informations about the gate and its source.
Thanks RoGeorge, I will have a look at what you sent !
Thanks Retirednerd2020, I will have a look more efficiently on the datasheets
Sorry I couldn't answer earlier.
Thanks again