NexiGo Enhanced Charging Dock with LED Light [On/Off] for Oculus Quest 2, [Support Elite Strap with Battery], Headset Display Holder and Controller Mount, 2 Rechargeable Batteries, USB-C Charger

If it were me, I'd just fill the gap left by the missing "leg" so it doesn't compress/lever out. Then install a rechargeable battery that can be recharged without needing to remove it.I have the NexiGo Enhanced Charging Dock with LED Light [On/Off] for Oculus Quest 2, [Support Elite Strap with Battery], Headset Display Holder and Controller Mount, 2 Rechargeable Batteries, USB-C Charger because it works with my Kiwi Design controller grips after trimming the bottom a bit as shown in their pictures. Otherwise... If you can find a small vinyl or silicone grommet that fits it'll probably be enough to keep it in. You might even find a shallow flared plastic button from a broken game controller or something that you can drill hole through for the battery terminal then cut some slots into so it's close to the original "legs."