Position and style of back button in web - User Experience Stack

After studying about the 'Back' button, I still can't decide on which best suited my case. I am designing an internal portal where the content varies in width. Button position: A.1 Right side seems

navigation - Positioning Back, Cancel and Next in a full screen wizard - User Experience Stack Exchange

Designing for Action: Best Practices for Effective Buttons, Wireframing Academy

Crafting Intuitive Mobile Navigation: Design Patterns and Best Practices, by Sourav Mahapatra

What is Full Stack Development? [Frontend + Backend]

Designing A Better Back Button UX — Smashing Magazine

navigation - Positioning Back, Cancel and Next in a full screen wizard - User Experience Stack Exchange

Understanding navigation - Material Design

website design - Should a web-based UI rely on the browser back button? - User Experience Stack Exchange

Back Button UX – Smart Interface Design Patterns

Designing A Better Back Button UX