Melee is mostly bound to weapons and the actual level of your character doesn't matter
Well, if progression is the only thing you care about, spell casters will give you the best experience as a new player because they literally scale as you level up. In fact, the only thing that will give you significant damage boost is going to be the level of your main spell. Difference in damage between a level 20 and 21 spell gem is going to be around ~15% increase. Level 20 vs 24(so a lvl 21 gem with a lvl 4 empower support) would almost double your damage.
Melee is mostly bound to weapons and the actual level of your character doesn't matter. If your weapon is bad, so will your character. There are hundreds of leveling unique weapons and most of them are going to be better than whatever you can get from a spell. Melee doesn't require constant increase in links, either. Just change your crap weapon for a better one and you're set to continue your journey.

May
Top 5 Builds for PoE Flashback League
I have been playing Flashback league for about two weeks, and I do have a lot of try in this one-month league, yes, I mean I have checkout so many builds that would be suitable for Flashback, I found Top 5 of them, so I'd like to recommend you these best PoE Flashback builds to you:

Aug
poe4orbs:[Lake Of Kalandra] PoE 3.19 Ranger Starter Builds
Here is the latest PoE 3.19 Ranger League Starter | Fast | Endgame | Cheap Builds brought to you by PoECurrencyBuy.

Dec
Poe4orbs New Promotion, and this promotion
Gold to see you again. Poe4orbs appreciate that you had ordered on Path of Exile Currency on our site before.

Dec
The only unique I am chancing for is Skyforth
He said that they initially planned on introducing more bases to the glorious plate to make chancing Kaom's Heart harder.

May
Path of Exile Level And Gear Guide
We all know that there are a lot of maps in Path of Exile, which can be used to level and gear. But you still need a detailed guide on how to do these step by step, so I am going to show you.