as for pressure on your stomach while you sleep pushing acid etc. - that sounds like something losing weight would solve.
when men get older most of their fat is stored viscerally ( as opposed to babies who store fat under the skin or women who store it on their hips ). i can see how this could be pushing on your stomach.
losing weight would be worth it for you regardless of what is causing what.
trying carnivore may or may not reveal any benefits.
maybe lose weight first if you still have stomach issues then try carnivore.
or maybe trying carnivore will help you lose weight.
my only issues with carnivores is their lies that they don't need Vitamin C and that calories don't count. so my problem is with Carnivores ( scum ) not with Carnivore diet ( decent, when supplemented with Vitamin C )