How can Shift+Alt+Tab navigation be enabled in GNOME when Alt+Shift cycles between multiple keyboard layouts?

Question

I'm using Ubuntu 18.04 and have used GNOME Tweaks(1) to restore normal keyboard layout switching behavior where pressing Alt+Shift cycles between enabled layouts. I've also used Gnome Settings(2) in an attempt to restore normal windows switching where Alt+Tab brings up a list of windows and moves the selected window from the most recently-used window to the least, and Shift+Alt+Tab moves the cursor in the opposite direction.

Keyboard layout works well. Window switching does not: Alt+Tab behaves as expected but Shift+Alt+Tab does not because it changes the keyboard layout rather than traverse the window list.

How can I restore normal Shift+Alt+Tab functionality when using multiple layouts? I know it's possible because I've read a blog post on how to do it once, however I was unable to find said blog post again.

Edit: Found it! See: https://www.guyrutenberg.com/2015/10/02/gnome-altshift-and-altshifttab/

Edit2: I believe this is not a duplicate of OS keyboard shortcuts conflict with apps keyboard shortcuts in GNOME 3 because it's specific to Shift+Alt and that specificity seems to have allowed for an acceptable workaround. See my answer below.

Notes:

The setting is under Tweaks > Keyboard & Mouse > Additional Layout Options.
Normal Keyboard Shortcut reassignment.

score 4 · Accepted Answer · edited Feb 05 '19 at 08:15

There seems to be a workaround that allows you to keep using both shortcuts normally:

Alt+Tab and Shift+Alt+Tab both work.
Alt+Shift cycles between layouts normally.

The only caveat is that reversing window traversal with Shift+Alt+Tab will also change the layout once. This is an acceptable compromise in my case.

The way this is done is to: