I experience that reading the metadata hanged in LRT takes very long.
My main problem is that it only reads the data of the miniature in view.
Ik have to keep scrolling throu the miniatures until I have seen them change.
If I try to render before and have not checked all the miniatures, i get a conflict during rendering.

Is there a smarter way?

I guess you are talking about reading metadata in Lightroom. Yes, it's not very fast, but once the process bar on the top left in Lightroom is finished, the metadata is there. Don't bother about the thumbnails, they will not necessarily update. And you don't need them to update. Just do the next step and export the sequence via LRTExport. All changes will be there.