So you believe in a liberal sharia where everyone can adopt sharia according to their understanding. Please quote some example from the Islamic history that this liberal sharia is actually the one which was practised by Holy Prophet PBUH or Khulfa e Rashideen.
Also please explain the contradiction in your post where after making the statement that there is only one sharia and then you already admitted shias have different sharia which needs to be treated seperately. I will go one step furthur that there are several sects in shaias and sunnis with different understanding of sharia. Should we adopt more than 70 sharias and treat all of them seperately. It is good that you are a tolerant human being who is sensitive to different sects and want to give them the freedom of choice to adopt their own sharia. But how will this system practically work?
As far as non muslims are cconcerned will you demand Jazya from them in your model of sharia? Remember Jazya or non muslim tax is prescribed in Quran in a sharia compliant society!
Well my dear, i want the same Shariah 100% same.. that was implemented 1400 years ago.. I don't think it was more than one..
Thats enough answer to cover all your questions..