Weight scale who works with GARMIN CONNECT

I have the Garmin Index S2 scale - it works well except for the body fat percentage estimate being worse than someone who has never met you guessing what it is. OK body impedence methods of estimating fat percentage are all iffy but the implementation here is crazily bad.

way too expensie....150€+ here.

Agreed, I think as a value proposition it should have been about 66% less money than I paid for it.

I've been down this road as well, I have a generic smart scale which works pretty well but there is no way to sync it with Garmin connect. I just manually edit an excel spreadsheet with the metrics I want and upload them to GC. 

If you only care about the weight, get a cheap Withings Scale (which are considered quite reliable). I've bought the cheapest Withings Body scale I found on a sale, it's app (Health Mate) syncs the weight stats to MyFtinessPal and from there the data go into Garmin Connect.

I have a Withings Scale (can't remember which one) and use https://smartscalesync.com/ to sync. It's $15/year.