Part of the problem (from my point of view) is that any of those "cheap" knives, especially any out of stainless steel, are worthless. Improperly heat treated for throwing, they easily crack, break, chip, etc... That's probably at least A reason that the D2s are chipping.
They need to be soft enough to have a bendy springyness to them, but hard enough not to deform at the drop of a hat.
Most "commercially sold" throwing knives are improperly heat treated, from a thrower respective, being way to hard. Throwers should be mid-40s to mid-50s at the highest.
Going with people who specialize in throwers is the way to go. My 30+ competition throwers (rotation, no-spin and MM) are all by knife throwing people who make throwers. They experiment with new versions all the time, trying to find that "perfect" thrower.
Any knife that tries to be both a throwing knife AND a decent "survival" knife (whatever that nebulous term means) is destined for failure. The example I always use is that you can have a good fighter or a good bomber but a fighter-bomber is too slow to be a good fighter and a has too light of a max payload to be an effective bomber.
Now, any knife can be thrown, (well, at least once
) and a thrower can be sharpened (but a good thrower won't hold a decent edge) for "survival", but for the long term, neither will perform satisfactorily.
Getting to points of balance, that varies with the person, the knife and the style of throwing. Everyone is gonna prefer something different. Many folks prefer point heavy for no-spin, others prefer center-balanced. Rotational knife POBs range from towards the pommel to center to towards the point.
I have no-spins that are butt heavy, point heavy and dead center. They all have their positives and negatives. Most of my Bowies are very point heavy.
I am not a good example to follow s I have a terrible history of making profitable knives, but my approach is to never make prototypes out of "good" or "decent" steel.
Every prototype I have ever made, whether throwers, Bowies, swords, daggers, etc - have been made using A36 plate, regular old mild steel. It's much cheaper than using L6, S7, D2, W1, 10xx, etc for making knifes that are "in development". I can make a dozen or more knives out of a chunk of A36 for what the "good stuff" costs for a final product.
What a knife looks like on paper is useless if the thing doesn't fly right, release right or hit right. I've thrown knives that are useless as blade held throwers, funky looking handles that won't EVER release right, that look cool but flutter like wounded ducks when thrown. The type of steel has absolutely no effect on how a flies, but profile, balance and smoothness of release does. The type of steel only affects how well the knife performs long term.
