Libreoffice LanguageTool custom dictionaries

I have searched for a few days now, and nowhere is it clear, how Languagetool standalone or as extension** on libreoffice writer, interact with respect to the custom spell check dictionaries. I have all free versions of LT, on windows 10. and whithin libreoffice,

I can hack the libreoffice personal dicos, however, I would have liked to be able to upload it or share it with the stanaalone version (for on some slower machine the now huge LO, seems to struggle with background LT work (I might try the free server, but then I am not sure that the person on that computer will know that they might be asking too much of the free channel API).

Could there not be some import export between standalone (or web, they seem UI-identical) and libreoffice integated LT (or with extension).

BTW, is there any conflict having both in LO. (also, should I make anothere post of the intergrate/extension in LO UI problem: non-configurable minuscule font sizes both UI and content?)

** (I know, it has intergrated version, but I like to try all avenues, until I find something that works for me).