Boba is going to die and there will be no doubt that he is dead in ROTJ:R. How this is going to happen? Well, that hasn’t been fully decided just yet.
If I could venture an opinion, which would require some minimal filming and potentially some CGI depending on how elaborative a death one wanted to create for him - you could do it real quick like in the final battle.
In the film, Fett Lands on the Skiff and points his blaster, Luke cuts it in two upon which a blast from the Barge hits Chewie. Han yells about Chewie being hit whereby Luke looks down in concern on them - at that moment Fett shoots a bola rope around Luke and it twirls around him, Luke then uses his saber to cut the rope at the very second the skiff is hit with another blast from the barge.
My suggestion is that instead of Fett being knocked down to the floor of the skiff before Han accidentally hits Fett’s backpack to send him off the skiff as in the film - what about that blast literally hitting Fett because Luke cutting the rope causes Fett to stagger backwards into the blast which sends Fett careening end-over-end off of the skiff with smoke trailing his form (like the Biker Scout blasted off the Speeder Bike by Chewie later on) into the sand below? Get rid of Han doing the “Boba Fett? Where?” moment. It would showcase the inferiority of Jabba’s goons and also show that stormtroopers are not the only bad shots in the galaxy. Then you can have some playtime with Fett’s ‘death’. You could for example have a tentacle from the sarlaac wrap around Fett as he is trying to get up from the sand and have it drag him under the sand ala ‘jaws’ and instead of the belch we saw from the vagina in the crater in the original, you could change that to a burp from the sand that Fett was dragged under, that sends up a geyser of sand and some of Fett’s armor, gauntlets and helmet, minus the man who once wore them. I think that would solidify Fett’s ‘death’ and it’s done in a way that is in keeping with the way Lucas might have otherwise done it without the lame attempt to make Han’s blindness comedic.
Just a thought.