You've probably laid obstacles in your way by owning consoles, videogames, smartphones etc. if you want to build a good work ethic you need to begin with small incremental gains to the amount of time you spend studying (maybe push yourself 15-30 minutes longer each 1-2 weeks)
Sell your gaming devices, have a strict studying room with a cheap PC which cant operate games, block all social media, youtube, chans, etc.
Gradually over the course of 6 months if youve stuck to it you'll have at the very least 6hr30min+ study potential.
TLDR: Don't fight yourself and exhaust will power by having temptations be accessible, remove the temptations until you've built a study ethic and then reintroduce any vices slowly.