ok I've changed the batterie with a new one but similar problem unfortunately https://photos.google.com/photo/AF1QipO8Xp7elP9mX1X52sW5IauepMpYNLB9NrEuNpXL. Any other idea maybe ? Thank you!
Thanks a lot ! I've ordered a battery and cranking tester https://www.topdon.com/products/battery-tester-artibattery101 to get started with ruling out the battery and stater parameters based on your feedback then. Thanks again so far!