Strange, I don't have that problem, not juicy enough. Maybe you can try grinding your leaves finer? Or some of it ground really fine like dust and some of it a bit coarser. I cook mine in the instant pot for 4 hours, and leave it in there for another hour and let the pressure release naturally. If you're doing a quick pressure release, that could affect it. I've seen food cooking videos that mention a quick pressure release changes the texture of meat.
I might try 3 hours cook next time because 4 hours is probably not needed.
I don't think the problem is your leaves aren't dry enough. I just leave mine out in bags and boxes for a few days or weeks. When I do grind them, the leaves are still a bit pliable and not bone dry. I mix mostly Burley and Virginia and whatever else I have to throw in, I'm not real picky. Also, if it ends up tasting bad, that's nothing that a lot of flavoring can't fix. I tend to be more accepting of how it tastes and just go with it, if it's not what I expected I either get used to it or flavor it. Eventually I'll figure out a blend that I really like, but in general snus is an acquired taste, so I just adjust to whatever I make.
Whenever I made snus, the taste is always a surprise to me. I'm still new so I'm always trying different blends and additives to figure out what I like and don't like. And if you're adding ground mid rib, you could take that out. For me adding in midrib makes it a whole lot of nasty in terms of both taste and mouth feel. I also put it in my lower lip like American dip, it juices a lot more lower lip than upper lip.