Is there a jacket that can store my laptop and various heavy stuff? I'm trying to lower the weight of my bag

Perhaps unsurprisingly this is a thing.. some of this will depend on the dimensions of the individual items you need to carry and your clothing size but the range from SCOTTeVEST seems to be the sort of thing you're after. IIRC they used to do one that you could actually fit a "full size" laptop in but a quick skim through the site suggest that they might not any more.

I can't testify how good these are - or how comfortable they are when loaded with all the stuff they purport to be able to carry at once, since I've not actually tried one.