Destiny 2 , stuck on level one.

If You will finish story company, You'll rise near of max level, but main parameter in Destiny not your level, your light

I dont really pay for those types of things, as i see it as a waste of money bc i can simply play the game and earn xp for that

Why not just play through the game as normal, you will get to level 30 through storyline questing, events and strikes.

Many games now give an option to pay for something or to grind your way to it.

Personally I always grind. 1 because I hate to pay money for things like that and 2 because you get more game that way and get more value for your money that you paid to get the game.

Theres a discussion around loot boxes which is virtually the same discussion around pay/grind . I think having a pay option is ok if it doesn't give someone an advantage that way you can choose instant attainment or play for reward without being pressured
to pay to keep a level playing field

I personally wouldn't do that. The amount of time to get to level 30 is a drop in the bucket compared to how long it would take you to get to a decent light level.