Next Steps: GoPro/Insta360 --> ???

Hey all...I want to upgrade. Been using GoPro and Insta360 x 3 for a few years now and getting OK-ish results. I have a few sweet trips lined up the next few years (Socorro, Cocos Island, Palau) and want to up my game.

I currently have a Nikon Z8 with a few pretty nice lenses. I think the only one that would work underwater would be my z14-24/2.8. I don't have a 24-70...have never really gelled with that range. My goal is large wildlife, expansive shots. I am not super into nudibranchs, sea horses, etc. Think sharks, rays, whales, etc. Any issues with a Z8/14-24 rig for what I am looking to shoot? I would like to avoid another lens if possible. But if

Before I go this route....any recommendations for "intermediate step" options? The Z8 route is spendy and if something much cheaper will get me most of the way there, that would be great to explore.

Best!