Downloadable maps to MacOS HD for basecamp

Hey guys, so I feel like I've been running down a rabbit hole because the "downloadable" maps are very misleading. I have a Fenix 5x that I use for backcountry skiing. I wanted to utilize basecamp to plot and map stuff so I purchased the downloadable 24k Topo west so that I could install it into basecamp and run off my hard drive. Taking my watch off and waiting for the maps to load is a HUGE PITA and figure if the maps are installed it would be much easier. I have not found a way to download the maps to the hard drive but thought I could then buy a blank Micro SD (I bought a SanDisk Extreme 32gb Micro USB with Adapter) install the maps on the SD and use it that route.....and now it seems like that is not possible. Does anyone have any ways to try get the maps onto my hard drive to run in basecamp? Am I just completely missing a step or did Garmin REALLY make it this hard to buy use something you've purchased? Running Catalina, Express and Basecamp ALL on the latest updates.