This is how I was able to get my current blood sugar on my Garmin watch using a Libre2 chip and an iPhone 14 (also tested on an iPhone 7). If you get stuck or feel like you would like help, feel free to reach out to me on instagram.com/jeppewelling or jeppewelling gmail com
It is possible to set it up 100% for free. Follow the steps below.
Before you invest too much time in setting this up, make sure that your watch is compatible with the Nightscout plugins in Step 3 and 4. You can verify that by following the links and check that your Garmin watch model is on the list of supported devices.
First of all you need to setup a Nightscout instance. (Read more about Nightscout). There are many options for setting it up (you can see them all if you follow the Nightscout link). I recommend setting up Nightscout on a free Google Cloud instance. The amazing people from xDrip has made a very nice guide on how to do that. It takes about 90 minutes, so make a cup of coffee and follow every step very careful and you should be good:
After installation the default units in Nightscout will be dl/L to change this, follow the guide to set env variables: https://navid200.github.io/xDrip/docs/Nightscout/NS_Variables
Then add:
DISPLAY_UNITS=mmol
You need an app on your phone that can send data to your Nightscout instance.
I personally use Shuggah and I am quite satisfied with the app.
Zukka is a new alternative similar to Shuggah.