I recommend an Organic Acid Test (OAT). I've been struggling with gut problems similar to yours for years but then it got so much worse during the lockdowns. At the time I survived it by embracing fasting and keto diets but that wasn't much fun.

More recently my OAT discovered fungal activity and an enormous vitamin C deficit. Potentially this has been going on for more a decade and it would explain why I'm so tired all the time. Treatment through supplementation is in the early stages but I'm already feeling noticeably better.