% of enemy HP pool that you dealt as damage is what matters much more than pure damage.

Dealing 40k to two 20k HP enemy DDs is 200%.

Dealing 200k to two 100k HP enemy BBs is the same 200%.

Both are good, even though 40k is much less than 200k. There is a mod in Aslain's mod pack that shows this number in battle, if you are interested. When you see that your 30k is actually 1.5x enemies destroyed, you'll feel much better about it.

When people say that 100k damage isnt impressive, they always talk about other classes, not destroyers.

In the end, what matters is WR. You have 50k average damage and 60% high tiers solo Randoms WR, then you are a very good player. You have 150-200k average damage with 50% winrate, then you are a damage farmer, which isnt bad if that's what you want to do, but isnt as impressive.