Switch International English keyboard to US layout [duplicate]

I received the new M1 MacBook Pro running Big Sur 11.4. My company ordered it with an International English keyboard. Layout we all know is shown below.

I use the backtick "`" a lot and the tilde "~" to point to my home directory a lot too. They are placed incorrectly and I would like to bring this key back up next to 1, 2, 3 ... like in an US English keyboard.

I have obviously went to the Keyboard layout Input Sources but when I add and select U.S. , nothing changes and my keyboard layout remains the same

What choices do I have, without installing Karabiner or similar apps?

You're going to need Ukelele.
They're not placed 'incorrectly', they're simply placed where an ISO keyboard has them.
A US ANSI keyboard doesn't have that extra key next to Z, but that's where the rest of the world puts its backtick & tilde. (We all think the US is wrong… it's simply a matter of perspective ;)

Simply changing the input language does not, in itself, change the fact that key is recognised correctly as being an ISO keyboard, so some active remapping is going to be needed.

BTW, Ukelele doesn't 'run as an app' once you've finished building your new layout. It just aids in building the layout, which is then accessed like any other.

There's an alternative idea, untested…
System Prefs > Keyboard > Keyboard > Change keyboard type
When it gets to the part that tells you to press the key immediately to the right of left shift… press the z key instead of tilde. It might just force it to be [falsely] recognised as ANSI.

The top answer here includes a link to a custom layout that probably does what you want.