All these things are unusual:
1. You joined early enough that you can early exercise for such a low price ($7k)
2. Your company allowed early exercise (still unusual these days).
3. The startup 20x-ed in value (my conservative estimate)
4. You stayed in the job for 6 years!
5. Your startup let you sell some of your shares before exit (This is extremely unusual still).
Still, even with those assumptions this turned out only ok. Assuming you sold everything in December, you made $1.3 million over 6 years, so $217k per year. Considering that for a typical senior software engineer, the equity portion needs to make up about at least $150k of compensation (conservative estimate of a Google L5 from levels.fyi), I would say you did roughly ok, making an extra $67k per year. That's pretty good, but not amazing. Getting promoted to L6 would be more than twice as good.
Sorry for being so negative about your good situation, but I really think current equity compensation is far too low and tricky, and that workers, and especially new workers, should not be optimistic about the benefits.