using hidutil to map two keys to a single key
There's a third-party application called BetterTouchTool that will let you do this (and a ton more) quite easily.  Unfortunately, it's no longer a free app. However, it's an amazing app that's worth far more than it costs if you ask me.

For the record, no, I'm not related to the product in any way.  To the contrary, I'm a long-time paying customer who donated long before the dev started charging for it. At this point its so critical to my daily use on a Mac I feel completely lost without it.)