IT contractor to one client, no expenses - EURL or SAS or other?

I have been IT contracting through an agency to a single big client, I started as auto-entrepreneur but I am hitting the limit.

Estimated income for year will be around 140,000 euro, with my wife as auto-entrepreneur making about 5,000 euros. I have no tangible expenses, I work on site with no transport costs. My research all suggests this is a very basic situation but I can’t find a worked example that shows the difference in outcome of entreprise unipersonnelle à responsabilité limitée (EURL) or société par actions simplifiée (SAS). Can you give me some guidance please?

Friends and accountants have suggested I also consider SAS and mention dividend tactics but as mentioned I am struggling to make comparison to tell the difference and would need to pay a good portion as monthly salary I think. It seems I should be able to set an EURL up by downloading standard statutes and run it myself with a French speaking friend to guide me, whereas for SAS it seems there are lot more annual accounting costs involved.

1. So is my understanding of EURL basics correct?
2. Are there any implications to turning of my Auto Ent and moving to EURL?
3. Can you please explain the EURL calculation and differences to SAS?
4. Given my simple situation can I do the accounting myself?