How to reconcile them? The most obvious way: the second quote is referring to someone living an ascetic life, based on minimal work, and not living off donations. Note that the second quote does not say that the person can completely abandon all business affairs and be supported by others.
You are misreading it if you think he is still supporting himself on minimal work, since the entire point of the rambam is to say that these people gain the status of leviim, and don’t have to join the army or any other societal burden, and are given there food from Hashem the same way the leviim are (through an obligation on us to support them).
If you want to answer the contradiction, why don’t you take a look at what the acharonim say. I’m sure you’re not the first one to ask this. I would guess out of mein boich, that the difference is whether your intention in the learning is to be paid for it, or if you are just learning l’shma and other people are giving you money like their obligation is to do.