i haven't looked in a long time, and it's been decades since ive even ventured a peek at the darknet, but have you tried looking for .ne sites on the clearnet (the country code for the netherlands, which has almost universal recreational). you'll most definitely have to try a few sites (and check in with reddit and/or bluelight to make sure they're still operational), but it shouldn't be too hard to find somewhere that ships to most countries, and is morally [corrupt?] enough to list drop shipping partners to get into any country thats not covered.
i think last time i took a peek, i found 5 or 6 that fit all the criteria, in around an hour?
EDIT: also, i hope you're not trying to use benzos as the only part of your method?? despite media outrage during the "xandemic", benzos alone has incredibly low lethality; most deaths are caused by aspiration, as benzos do not slow respiration, and only have a tiny effect on heart rate (despite being classified as cns depressant lol). i can dig up the figures if you like, but i think it's only something like 2% of all benzo related deaths are caused by solely benzos, most of which, were due to secondary conditions (i.e. aspiration on vomit, suffocation from falling onto pillows, etc.)