There is no way to create the LUTs in Lightroom Classic. Therefore, you'll still need to use Camera Raw for this purpose. However, to import any LUTs you may have purchased or already built but are not yet accessible in Lightroom you need to import these via the Profile Browser in the Develop module (see below screenshot).
Also, this link will take you Lutify and provides some guidance that may prove useful
As of now, the only way to make creative profiles from LUTs is one-by-one in Camera Raw, as you've discovered. When creative profiles were introduced two years ago, several of us asked Adobe to document the .xmp format so we could provide plugins that made it easier to create the profiles and to handle LUTs in color spaces not supported by Camera Raw. Adobe finally responded last month, but I'm not aware of any plugins yet that provide batch conversion functionality. (It's down low on my priority list.)
You could use my Apply LUT plugin, which would let you import all 527 LUTs and apply them to photos within LR. The advantages of Apply LUT are its ability to batch import LUTs and its ability to handle LUTs in more color spaces, in particular Rec 709 Gamma 2.2 and 2.4.
If your LUTs come from the video world, then most likely they are in Rec 709, which is close but not exactly the same as sRGB -- you can notice differences in shadow detail between the two. Adobe has ignored requests to add Rec 709 (likely the Camera Raw developers weren't familiar with the video world).
The disadvantage of Apply LUT (which I developed before Camera Raw supported LUTs) is that, as with all external plugins, it creates 16-bit TIFF files (just like editing in Photoshop).
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