Kongi the Conqueror's Pancake FPS Starter Kit (opens in new tab) for Source 2 games is not primarily intended for playing Half-Life: Alyx, as the modder is at pains to explain. "Please don't use this to play Half-Life: Alyx and then complain about the game being bad!!!" as the GitHub pages puts it. "This was NOT intended to be used to play Half-Life: Alyx with!!! It is intended to be a base for non-VR supporting addons for the Source 2 Engine to use!!!"
But guess what? People have been using it to play Half-Life: Alyx, including YouTuber Goutrial (opens in new tab), who combined it with several other mods for what seems like the ultimate non-VR Alyx experience. The Half-Life 2: MMod Team (opens in new tab) came up with a bunch of weapon sounds and animations, Jun Choi over on ArtStation (opens in new tab) modeled the weapons themselves, and then Shadow_Run on GameBanana (opens in new tab) combined those animations with those weapon models. Jeremy Lorelli on GitHub provided the Vscripts (opens in new tab), and when you add those things together what you get is a version of Half-Life: Alyx with first-person arms holding guns that you can shoot with your mouse.
Is it going to be the best way to play Alyx? No, it's a game designed for VR, of course that's the best way to experience it, what a silly question. But people who can't afford VR or find it makes them sick can use stuff like this to play the new Half-Life with and that's OK. PC gaming is all about messing about with mods and options to get everything the way you personally want it, and this certainly is a thing people want.