Have you run into performance issues or are you anticipating future issues? 18-24 tiles should be well within what the toolkit has been designed for. If you have encountered performance problems make sure you are testing in a packaged project. Blueprints run significantly faster in a packaged project compared to playing in editor.
If you do need a performance boost, blueprint nativization does not play well with the toolkit’s pathfinding. This is due to Engine issues with blueprint structs and TMaps. The best approach is generally to manually convert what you need to C++ in any case. The good news is that I’ve already done this for many of the toolkit’s expensive functions. So when you need it let me know and I’ll format the code and share it.