For what it's worth, 21S recently added a system that allows scenes to be bought individually ($2.95 per scene if you're not buying credits in bulk, less expensive if you do)...haven't tried it personally, so I can't vouch for how well it works.
Escaping from "same old mindless crap" is going to be difficult on any network...the regular update schedule practically ensures that scenes will start to look familiar to you after some time, just the girls change.
Since you're only planning for a short subscription, I don't think you can go too wrong with any of RK, BB or 21S, honestly. Even if the fresh updates aren't fully to your liking, there's years of archived content on all three networks. Not sure which site you're referring to by "Porn Pass" (Porn.com? Pornpassforall?), so I can't say anything about that.

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