Most mobile web browsers, use an action button to switch tabs. Also, this pattern is used in Androids and iOS to switch between apps.
Pros: This pattern is very forward in action as you get exactly what this is intended for.
Cons: This, however will affect greatly on the overall experience of the app. Users seek for something more comfortable from an app, they may get disappointed at the browser-like feeling it provides.

Tab Switch

enable the user to view a list of previous screens while a Single tap will, as usual, take the user to the previous screen. 
Pros: This is great for power users and also the best inspired use of our basic instinct.
Cons: Users might not always promptly remember that they can find a list easily by tapping the back button little longer than usual.

Long Press on the back button

Pros: Most of the people already know that if you tap on this three bar ( ☰ ), you will get a list of something!
Cons: But most people will tap this button to navigate to their profile, signing out and other stuff. If we use the same thing for going back, that might create some confusion and users might take time to get used to it.

Hamburger Menu

Pros: This is a great way to show users current location in the hierarchy and they can choose to go back in this hierarchy pretty easily.
Cons: Displaying breadcrumb in the mobile display isn’t an easy task. Many screen/activity may have long name that might create confusion.

BreadCrumb

https://uxdesign.cc/an-approach-to-solve-complex-backward-navigation-in-mobile-through-user-research-45d786a83bed

University of Michigan - Ann Arbor

Graphic Design References

Material Design Documentation

"10 great design systems and how to learn (and steal) from them" 
https://uxdesign.cc/10-great-design-systems-and-how-to-learn-and-steal-from-them-4b9c6f168fa6

"10 great design systems" Medium article

Reverse Navigation Typologies

IDEO Human-Centered Design Process

Interaction Design Foundation

Hanington, Bruce M. Universal Methods Of Design: 100 Ways To Research Complex Problems, Develop Innovative Ideas, And Design Effective Solutions. Beverly, MA : Rockport Publishers, 2012. Print.

Universal Methods of Design

Apple Human Interface Guidelines

https://eng.uber.com/introducing-base-web/

https://brand.uber.com/guide

Uber Base Web Design System

U.S. Web Design System

https://www.microsoft.com/design/fluent/#/

Microsoft Fluent Design Reference

https://spectrum.adobe.com/page/principles/

Spectrum - Adobe Design System

Carbon Design System

https://venngage.com/blog/graphic-design-trends/#Geometric-Shapes-Everywhere

7 Graphic Design Trends That Will Dominate 2021

http://blog.vaexperience.com/neumorphism-skeuomorphism-and-flat-design-march-2020-newsletter/

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