Diet change, like writing down the foods that give you a reaction. Some medications can help.

I think what will help depends a lot on what your main symptoms are. I personally take biokult (a probiotic) and dulcoease. Figuring out what foods are setting you off and what foods help and therefore should be trying to eat regularly really helps too. As well as eating meals at regular times. It's definitely something that takes time and trial and error, but it's definitely possible to get it to a generally managed point!

Stop the cannabis it will make it worse, you can go online to pubmed and read their studies on THC. It will make IBS anxiety and depression way worse. When they say it relieves depression and anxiety that is only transiently, long term chronic usage makes those things reallllly bad.

Try to identify your triggers. For me it's mostly coffee, sugar, and dairy. Since I know that, I can chose whether to have them (often I can tell if it's going to be a Bad Day, and I should avoid all triggers).

Something that has really helped me is trying to not eat greasy/oily foods as often or takeaways and strengthening my core with pilates or yoga, you can find 10 minute beginner core strengthening videos on YouTube if you haven't done it before that are relatively easy after a few days !!