I finally bought a bike! Its a Trek Marlin 4, 2021. Thanks for everyone from this community who suggested it and especially u/badger906 for explaining me a lot of basics : r/mountainbiking
Trek Marlin 4 Mountain Bike in Black
The Starting Point - 2020 Trek Marlin 4 Disc Feature Review and Weight - YouTube
Marlin 4 Gen 2 - Trek Bikes (GB)
Trek Marlin 4 Hardtail Mountain Bike 2023 in Matt Black