Note that raft is an old technology - not used much these last 7 years or so. It was used back in the day before PLA became popular and before heated beds when we just had ABS filament only. It was the only way to get parts to stick to a cold bed.
Now with heated beds, and ABS glue stick and PVA glues and so on, it's just not the preferred method. It gives an ugly bottom to the print when you remove it. And I suspect the makers of Cura have never used it for it's original intention so probably didn't make it very flexible (which is what you need so the part can shrink without separating from blue tape or whatever type of bed you have.
there's a parameter called "build plate adhesion type". Set that to "raft" and then all the raft settings will be accessible.
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