You can lighten the weight of Vivoactive 4 with a 22mm velcro sport loop band to 38.8g. It now weighs less than VM4S 18mm and Vivomove Style 20mm with the stock silicon
Bracelet Pour Montre Connectée Garmin Vivoactive 4 4s, Style Luxe, Pour Garmin Venus/vivoactive 3/garminactive S/garminmove 3 - Bracelets - AliExpress
Best quick release bands for Garmin Vivoactive 4 | iMore
Montre connectée Garmin Vivoactive 4 Silicone Grey - Daniel Gerard
Garmin Vivoactive 4 GPS Smartwatch in Slate and Black | HSN