Perhaps controversially, I'd go Revenge of the Mummy here, and by quite some distance.
I've always liked ROTM; I love the theming, and I think the ride is pretty good from memory, too (although granted, I haven't ridden since 2016), with some fun launches and an exciting layout! Certainly a solid 8/10 coaster, and it sits in my top 15!
Everest is all right, but it always leaves me feeling slightly cold, and I'll admit that I don't get the hype. It's a perfectly fun family coaster, it's stunningly themed, and it has some nice tricks to it, but if I'm being nitpicky, it isn't the most dynamic in terms of transitions compared to others I've ridden, and it feels a tad stop-start, with the bit where you're stopped for ages in front of the broken track really killing the flow, in my opinion. I've always heard people wax lyrical about it, and I went in super hyped, but I was bitterly disappointed when I first rode it and even though it's a perfectly fun ride, it always leaves me feeling a tad underwhelmed. It's still a perfectly fun ride, though; a solid 6/10 for me, and sits at #40 of the 91 coasters I've ridden.