Which hero to buy for beginner to level up faster and useful for future?

All the heroes are the same.

False! - Each hero has different base stats. I'd say a heavy hitter or buffer.

You should buy a hero of each job, doesnt matter if it's 2000 jewel hero or not because you can maximize the stats later with jewels to be the same as a 2000 jewel hero. I recommend promoting heroes to maximum of 5 stars one by one and level up the equipment and skills too. I got a team with battlepower of over 7 million in just 11 days since I began playing. I also recommend using honor points to upgrade your level up power and level up your heroes with silver. Buy artifacts that heal heroes after stage and revive slain heroes. Also you should put your phone to a charger and leave the game open when you sleep or watch a movie so you gain more silver faster.