Hi there ColliFlyer,
I do understand your frustration of the matter, but we have to look at it realistically. Laminar Research have received many bug reports over the few weeks of current Beta, and low fps is on top of there currently known bugs, but they're still optimising rendering and it may take a while until that optimising is finalised, where they'll feel comfortable to put it into a Beta version or slip it into final release.
If you'd like a full list of X-Plane 11.00 Release Notes, Beta Updates, Known Bugs and more, please visit this page here.
I hope I was able to help.
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