A setting for shortcuts

If I am understanding you, then uncheck Use Shift key for tool switch in Preferences.  Why would you want to use two keys when one will do?

Click on the three dots at the bottom of the Toolbar and choose Edit Toolbar.

Drag any tools that you never use to the right to remove them from the toolbar. 

For tools you rarely use, click on the shortcut and delete it and click to check Disable shortcuts for hidden toolbar extras.  I very rarely use the Pencil and Color replacement tools, so when I hit B I know I am selecting the Brush tool.

If you have the screen space, rearrange the tools to make them more accessable with the mouse.  

Set up your favourite workspace, and save it making sure to check Keyboard shortcuts, Menus and Toolbar

that setup will now be locked to just that workspace.  

This also allows you to make more use of the available shortcuts making contextually useful according to function.

For instance, I use these shortcuts to arrange document windows, but Shift Ctrl Alt T is the (hidden) shortcut for Free Transform Step & Repeat, so I switch back to Essentuals when I need that function.

I take it a stage further with short actions that set, and reset my most used workspaces using Function keys.

Note: the reset part is important as it tidies up the worksace, and I am forever moving panels about to get screen shots for forum answers.

IMO Function keys are the forgotten and underused solid gold resource in Photoshop, as I suspect most users never/rarely use their defaults, and doing an often repeated function with a single key press becomes a luxury you'd hate to give up once used to it.

These are Function key defaults.  F1 is hard wired for Help and can't be changed.  The rest are fair game.

If I understand correctly, the solution is very simple and you don’t have to go to the trouble of editing any keyboard shortcuts.

In Photoshop preferences, click the Tools panel, and enable the option “Use Shift Key for Tool Switch”. When this option is enabled, repeatedly pressing the same key does not cycle through a tool group, unless you are also holding down the Shift key.