It definitely has negative effects long term. Concentration is impacted. In my case, it can cause anxiety. The impacts are subtle, but they’re there.
The negative side effects are definitely being underrepresented at the “non-scaremongering” parts of civilization.
For me, the downsides manifest as drarticlsly increased anxiety (I naturally have next to none), extremely poor sleep - I sleep but the sleep is so low quality it begins to feel like my brain barely works right, and the obvious one, the effects on your motivation. I naturally tend towards ADHD style dopamine chasing, and weed makes that about 100x worse. Instead of getting my work done, I will procrastinate with any number of cheap dopamine hits such as video games, internet sleuthing, etc.
You can just stop. Really. Go take a long trip somewhere weed is illegal (eg. Japan) and throw out your stash on the way out the door. You will be fine, maybe a little irritable for a couple days, but the trip will distract you and it'll be indistinguishable from typical jet lag symptoms. There is no biological dependence, unlike with most legal drugs such as alcohol, tobacco, benzos...
Have you tried blending in CBD?
Typically I smoke small joints with 90% CBD strains and the rest a high THC strain, only thing I can smoke.