The Garmin Edge run very well without a smartphone or even a computer. Bluetooth File-Sharing from/to Edge is built-in. And they can sync themselves via WiFi. I favor them over Wahoo because they work standalone :) And with Linux you can feed them via USB easily.

The fitness-trackers without a smartphone are more problematic. They’ve WiFi integrated but I think they sync only via Bluetooth and the smartphone? Syncing via Garmin Express should be possible only on macOS or Windows. I think they provide also USB access on Linux.