https://modrinth.com/mod/dynamiccrosshair

This mods solves a problem visible in all of your screenshots: the crosshair being visible behind the transparent UI

There is most definitely a way to configure it to act exactly like the vanilla crosshair except for it's disable rendering when a UI is open, but I haven't written out a proper guide on how to configure the mod as such.

Amazing. I'd been using that for a while now recently and didn't even consider it for AquaHUD.