Loading a dictionary is not enough. Spellcheck requires also an engine to run.
You didn’t tell how you installed LO. The most difficult way is to do it through the LO download site because what you find there is not optimised for the thousands of Linux distributions which exist in the world.
You should use the package manager which comes with Garuda and install the required packages for the target language. The common spell-checker engine is hunspell. It should be automatically installed if the dependencies are correctly set in the target language pack.
To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!
In case you need clarification, edit your question (not an answer which is reserved for solutions) or comment the relevant answer. Notably, give some information on Garuda (on which major distro is it based?) and your target language.