Recently I found how the karoo store the heatmaps from suunto, but theses heatmaps are just very basical.
This is something like the slippy map tiles from openstreetmaps (https://wiki.openstreetmap.org/wiki/Slippy_map), so this is very similar to the kmz files, I update my program to support this type of tile creation.
So I share my solution if someone else is interested to import strava heatmaps on its karoo.
https://github.com/jarod46/Strava-HeatMap-To-Tiles (just download the last release on github)
-just start StravaHeatMapToKMZ.exe and install .net runtime if asked, I think you also need a recent computer with microsoft edge installed too)
-disable location permission in the navigator window and connect a strava account to get high resolution maps
-zoom on the part of the world you want to capture
-in program options (not in the navigator window) leave map style option to none to have a transparent background
-choose desired activity type
-leave tile size and tile zoom options on 512/14, 14 is the biggest zoom value used by karroo/suunto heatmaps, it's the most useful zoom, used while navigating
-click on "create tiles", and select an empty folder where to save tiles
-now you can send tiles on your karoo, manually, or by clicking on "send tiles to android device" button
-you need android tool adb.exe and your karoo in developer mode, if you already sideloaded some apps on your karoo, you know what I mean, see dcrainkaer guide if you don't (https://www.dcrainmaker.com/2021/02/how ... roo-2.html)
-select the adb.exe path and the tile folder chose before (you should see a directory name "14" in), leave "android device remote path" to default for karoo devices
-be sure to have the karoo connected in developer mode to your computer and click on "send"