Well OP you can do a lot with a little. After you find a way to easily extract whatever you want from the internet and get the essentials down like a decent external hardrive or 2 to keep all your stuff safe start working on making everything more comfortable for yourself. Have something else to live for, just watching movies/anime and playing games all the time alone will get boring. Make your room look nicer, take advantage of having all the time in the world and go for walks outside sometimes when it's nicer and exercise (it'll make you feel better in the long run plus you get to go on little adventures making your life more interesting. go to stores and stuff too, have fun exploring the world on foot.), buy a lot of junk food from small shops and the dollar store to horde in your room, learn how to cook and throw in some tasty but cheap dinners every so often with your usual frozen food heated up in the oven or microwave, get into something like meditation to ease your mind even more, and the best thing is you can indulge on whatever interests you to the fullest as a NEET. Just try to live for something and make life more rewarding and fun. Do what you can with what you got.
As for drugs with no connections your limited to stims and over the counter shit unless you can somehow get medical marijuana (I wish I could so bad). Gas station shops and the internet have some pretty powerful energy drinks you can buy that mostly go buy unnoticed by the public (which is probably why they haven't been pulled everywhere.) like Spike Shooter for example which will get you high as shit if you down the whole can at once quickly. Another among the top most power drinks is Redline but I don't recommend it, all stimulation and paranoia with no euphoria. You'll just feel like you've lost your mind after a whole bottle of that stuff downed quickly but if you want to feel that go ahead. There are more powerful than ordinary energy drinks too that aren't like the usual ones you can down like soda but won't get you too high either. Then you have the energy shots they're only good for a little boost but one of those during the day can boost my mood a bit. The only one I can ever say that actually made me kinda high was a Spike Double Shot, felt pretty nice. Can't find those anywhere around here though in any shops. There is one other way I can get high but it's self harm and I don't recommend it to anyone because of that but if you want to I'm not stopping you. I can get extremely high on my own endorphin releases through a ghost pepper based hot sauce which is Mad Dog 357: Ghost Pepper Edition. I fill the cap and very slowly sip and spread it around my mouth and swallow with each sip. Do it wrong and you'll just hurt yourself very bad and have milk around to ease your stomach. Very soon I'll start to get more relaxed, then all of sudden I'll start to feel floaty and everything sounds better, then I feel warm and my body feels like it's vibrating, and I'm in total euphoria. I get some closed eye visuals like colors and shapes, just closing my eyes and alternating between laying on my bed or sitting on my chair with music is a great experience. Only outer visuals I ever got was a little hardly noticeable movement on the surface of everything like tiny waves but that was the highest I ever been.
And there you go my guide to being NEET while still living a fulfilling life and being mostly satisfied.