I'm quite interested in these as well. I contacted David Pearce just today before seeing this to see if he has any connections or a supply of JDTic and I also sent an email to science.bio concerning the addition of the product to their store which they said they're possibly looking in to. I'm in the same boat as you as far as finding the kappa antagonists since I don't have any university creds and I'm unemployed.
I'm willing to drop a significant chunk of money to fund a group buy if you can find a reliable source. I've got 2 grand to burn so if you can find a supplier that's very reliable that can at least send a sample first I'd be willing to fund most of the group buy and sell off my supply to the rest of you. I understand this sounds sketchy as I'm a new member but I'm a long time lurker and this thread caught my eye enough to make me make an account. You add me on discord (Targz#8589) if you're interested (new member message limit), there's a pretty large server I'm in where several people are also interested in buying a kappa antagonist and many of the members there can vouch for me that I'm no scammer.
I have a very close friend with TRD and DP/DR that could really benefit for this, and I've been scouring the internet hopelessly for the most of the day.
As per your 5-HT2C issue though, you may be able to get a quick fix with a sigma-1 agonist, which counteracts the effects of inflammatory cytokines in the brain. Inflammatory cytokines upregulate 5-HT2C receptors and the SERT, and sigma-1 agonists block the effects cytokines have on serotonin reuptake and 5-HT2C receptor sensitivity. Considering 5-HT2C supersensitivity may be a product of inflammation in the brain and body, a sigma-1 agonist such as DXM might come in handy. I can vouch that low doses of DXM (75-120 mg to start depending on your weight, taken on an empty stomach) give several hours of increased motivation before requiring a smaller redose whereas SSRIs have always caused lethargy and fatigue in me. Fluvoxamine may also be an option but I found the "sigmaergic" effects to require too much serotonin reuptake activity before becoming relevant whereas DXM (without a CYP2D6 inhibitor) caused a more reasonable, balanced effect rather than feeling "off" or "chemical."
Though a 5-HT2C inverse agonist would be ideal (even the sigma-1 agonist option would likely decrease the amount of 5-HT2C receptors depending on the dose rather than just blocking them neutrally, meaning less constitutive activity overall, though at what point this effect becomes relevant compared to a clean antagonist is unknown), I think a kappa antagonist is far more interesting and has far more merit, especially considering that 5-HT2C receptors also mediate oxytocin signalling in parts of the brain, so blocking them outright might be undesirable compared to decreasing pathological effects of cytokine-induced overexpression through sigma-1 agonism which also has BDNF boosting antidepressant effects, boosts NMDA receptor expression in prefrontal cortical working memory networks, and increases acetylcholine release in the cortices, contributing nootropic effects as well. Kappa agonists seem to be the most in demand, and are probably what you'll find more people interested in.