Magic Mask recommended steps

Hey,
I have some problems using magic mask and would be glad if someone give me hints or tricks on how to deal with those.
After the mask was created and tracked - how to I "lock" it - or maybe "cash" it? It's 0,5 fps at best even after tracking. I would imagine tracking should be a one time process and then I should be able to work with that fairly normally - but now it's unusable.
The only way to even preview it is to use timeline cash (smart or user) but still - whatever I do to or around a clip - it recaches so that's not useful. So I'm assuming it is a user error.

What are the step I should do to be able to work with magic mask?

I'm writing here because maybe it is a bug?
Lastest beta for M1, MBP M1 8/512.

There have been other threads on this, if you search. Turn off Mask Overlay and it should play in realtime.

You might also need do right click on the thumbnail in Color and choose Render Cache Color Output. When I do that (with Mask Overlay off, and correction applied within the Magic Mask) I get realtime playback in Color, after one slow play through.