It’s kind of a gray area as far as my knowledge on this. I’m only making assumptions based on my experience. I have parts of my app that are slow too. The app initially loads fine, but when I switch to the tab that has the large amount of data, then it’s slow to load. I think in my case, I have a lot of data combined with a lot of glide computed columns, so filtered or not, I think the entire sheet needs to process through all those computations before it can display anything. In your case, you may be filtering you data by distance, but it still has to process all of those rows of data…so it would have to calculate realtime distance on all of those rows before it can even determine if they should be filtered out at all. If you have any other additional computed columns, like math, templates, relations, lookups, etc, then that’s additonal calculation that have to occur. If any relations refer to any other sheets, then I also assume it has to process the rows in those other sheets as well. All computed columns are computed on each individual device, so part of it also depends on the speed of the device and how much available memory it has.
If possible, I think it would be better to categorize your data first. Maybe have a sheet with just categories and that’s what you display first. Then you can drill down into each category to see items within that category. I’m not sure, but I think something like that may help a little bit.