You aren't Leveling on lvl 10 mobs in this game from the beginning, Enemies at level Parity are not depending on what they are Pushovers, especially in rags with starting weapons.

No the Mining unless you want to get blind sided and double teamed is indeed the "easiest" way to do it at start, because you aren't dieing.

Honestly the combat is pretty easy in this game for certain enemies, so I feel like the fastest way to level up would be to get a decent weapon and start fighting level 10 enemies

this is nowhere near as fast as just running around finding POI's