How important is it to consider NPC expertise?

I died to the same bloody pirate 3 times and paid more than 600K in ship rebuy costs. I was in a DBX then switched to my vulture, then I barely escaped after trying to go for a 4th time against him. He was an Elite in what I think was a viper MKlll.

The thing is, I took down expert and even Master ranked NPCs in much higher ships like the Python and the Krait MKll. So my question is, how important is to consider the expertise of the NPC that I’m attacking? And is it more important to consider than the type of the ship?

Edit: https://edsy.org/#/L=HN00000H4C0S00,E_d00HgB00,CEg00CzY00Dho00,9p300A7g00AOs00Acw00Aq_00B7G00BLo00BZY00,,7TM0005U00mpT4wY0068g000nG000nF00

Here is the closest thing I remember to my build, no engineering whatsoever.