Okay after reading up a bit and looking around, this all makes a bit more sense to me now. Thanks for pointing me to the right direction. I also found this video tutorial that explains how to replace instanced meshes with actors for interaction, which was a bit of a concern for me: https://www.reddit.com/r/unrealengine/comments/kmg2pu/how_to_have_30k_interactable_actor_foliage_with/
Just for clarification, if I use HISM I will need one HISM instance per tree model that I plan to use, correct? So using different kinds of tree models will make the setup even a bit more complicated.
Also, is there a good way to place the instances in the editor? I found the “instances” node for the HISM, but so far I am only able to put the coordinates manually for each tree, which is kind of tedious.