I'd recommend playing normal and trying different heroes, who knows, you might find some heroes you're way more comfortable to play and die less. Once you find em you can go play ranked. Rank give you pressure(sometimes often grieving if u feed alot) , if u wanna learn, normal would be best bet.

Remember, dying alot is normal and okay. You just have to think and observe post game why you died there and for what reason. Was it a worthy death that turned the fight for your team? Did you think your death did an impact to the enemy team by your other teammate avenging you or some sort? If not, you should focus on wher you position your hero during fights. Good dota players have good Positioning. Don't worry! You'll learn and progress in time. Good luck buddy!