Using Walk Navigation like Unity and Unreal I'm using Blender 2.8 and wanted to change some settings on the viewport navigation.
I always wanted some way to navigate in the 3D world like we can with Unreal and Unity. In this new version, I could changed the Walk Navigation mode shortcut to activate when I'm pressing the RMB. (You can do that by going to Veiw >> Navigation, Right clicking on Walk Navigatio >> Add Shortcut, and pressing the RMB)

That works extremly well, but when releasing the RMB, you lose the movement and the camera resets to where it was before. I can press the LMB, so it stays at the same place, but it's anoying to do that all the time. I think that happens just like you cancel an action clicking the RMB.

So, is there a way to cancel the canceling of camera movement by pressing the RMB? Or, is there any other better way to move the camera like that?

Thanks.
I'm not sure about 2.8 but in 2.79 you can activate it by pressing Shift + F this way you'll be able to fly around using W, A, S, D, E(Up), Q(Down); You can also activate gravity by pressing TAB.

Edit: you can also use the Mouse Wheel to change the speed of the movement, Up/Forward to increase, and Down/Backward to decrease it.

after you're done:
 LMB to stay in the same place or RMB to return to the original place.

I hope this solves your problem :)