After seeing some truly wonky screen protectors (even official ones) for cameras, I always go for one that's nothing more than a simple square of tempered glass. Sure, it's not optical-grade glass, but that doesn't matter on an LCD. If it works on high-res phones, it works on your camera. Easy to apply and clean, too.
I got
this one off AliExpress for $3.50. Has worked perfectly so far, including schlepping my camera aroun Vietnam and Cambdia for a month - including getting my backpack full of sand at the beach. Shipping is slow, though.