The best strap for the Galaxy Watch 4 classic turned out to be the new Fabric Band. The one in the package is crap, and the others: Sport and Extreme Sport are
Buy S/M Leather Galaxy Watch 4 Strap | Samsung Business UK
Samsung Watch Band, Strap for Samsung Watch 6 Classic 43mm, Galaxy Watch 6 Band 44mm 40mm, Galaxy Watch Strap 5, 4, Leather Band for Samsung - Etsy UK