....I tried to write this response to avoid spoilers but that was annoying, so I'm just gonna write it, and if someone hasn't watched the latest episode (days after it came out) then why are they in this thread in the first place?
Spoilers to follow.
I get what you're saying but I think you're comparing two slightly different things. Yeah, Walker is special ops and a highly trained soldier, but even the highly trained spec ops soldiers don't spend a ton of time mastering melee combat. The dora, on the other hand, are primarily melee combatants and they're trained to keep up with their superhuman king.
The whole situation was perfectly built to give the dora a huge advantage; Walker didn't know they were coming and basically got ambushed. He was forced into tight quarters where the extra reach of the dora's spears gave them a huge advantage and played into their training more than his own. And they're using vibranium weapons and gear, which negates the shield and surpasses everything else.
Not to mention we're talking about Wakandans. They all have access to technology and training that makes the best American options look laughable, and the dora are the best Wakanda has to offer. They're so good Okoye earned a spot as an Avenger during the five year time jump, yknow? And I'm pretty sure we saw Ayo protecting the royal family in Black Panther, which means she's one of their best, so it's not like Walker got punked by some random nobody who had just joined the milage.
In a different scenario I'm sure Walker would've had a better showing. Well, a different scenario *and* a narrative that didn't require he get beat to push him further towards the abyss anyway.