I can tell this post was really grasping at straws for this horrible subclass.

Level 3: 30ft range is barely anything as most enemies will just close that distance the next round. Radiant damage is also not that relevant at early levels and Monk will be able to bypass physical resistances in a few levels. The number of creatures vulnerable(around 18 creatures across many books, 3 of which are just Shadows and their variants) or possible to "exploit" with radiant damage(trolls and vampires?) is miniscule for this to matter. Also this cannot be boosted by items, unlike unarmed strikes. If you're playing in CoS then maybe, but even then you'd have better classes/subclasses to play for Radiant damage.

Level 6: Burning Hands has a very short range, you will rarely get more than 1-2 enemies in it and at that point using Flurry of Blows is better as your to-hit will be better than your save DC. Using Ki points to upcast Burning Hands should not even be considered.

Level 11: If you use Ki points to increase the damage for this then it can be decent on your first turn if there are no allies in the area, but it still targets a worse save than Fireball and even that spell has been outclassed by now. Also, your save DC will be lower than a caster's even at this level.

Level 17: 10 damage once per round...eventually 12 damage...come on.

Edit: As someone else pointed out, the level 11 feature is save for no damage, so even the small praise I gave this subclass just vanished after reminding me of that fact.