I feel sorry for you HappySeal, but it is going to be hard to figure this one out from here.
when you think it feels normal when you pull the clutch, it makes us think like Lineaway said. the clutches are kind of known to, while in storage I call it, squeeze all the oil out between clutches/metals. then it also kind of "vacuum seals" to each other.
So what you end up having to do (IF THE CLUTCH hydraulics is RIGHT, NO AIR, and IS WORKING) is, you start the Beta up, all while it is heading where you wont hit anything. Put the bike into gear while rolling forward best you can, then while riding for a few seconds, you pull clutch and tap rear break, until clutch lets go. My problem is that you have 2 issues probably, without knowing if the hydraulics is working, you might not get the clutch to let go. But, in large part, this is true on a couple old bikes I've had, doesnt take much to get them to let go.