what is the "WWE style"

This. It's about showmanship and responsible ring-work. It's not having reckless, spot-monkey, spot-fests, just for the sake of it.

WWE style is a distinctive in ring style that incorporates WWE's production and stylistic preferences. You can go back to the 80's and see a very different layout to matches between what Crockett or the remaining territories were doing and in ring and how WWF matches worked. Over time that style has evolved, and you also certainly saw elements of WWE Style trickle out into other promotions. But the basic structure is still there, and there are major differences between how a WWE match is laid out and what you might see in Impact, MLW, AEW, etc.

A lot of it has to do with a pretty specific pattern that they work in terms creating heat and a babyface comeback. There are also specific guidelines on how to work to the hard cam and a restricted moveset that ends up creating a lot of redundancy (like multiple suicide dives a night, or workers hitting a signature spot in every match).

There was a really interesting Twitter thread a month or two ago laying out how Sami has progressively eliminated signature spots since leaving NXT.

The style obviously has its fans, and is a big part of what allowed Hogan and Cena to get over huge with kids and families. The audience is conditioned to expect a certain type of match, and the product will consistently deliver it. Some guys work better within that environment than others, and some guys are given more freedom than others. The style has become a turnoff for a lot of fans.

The idea of moments is of course spot on, that's a very big part of it.

Another big big part is familiarity and homogeneity. The matches often have very similar pacing, traditional layouts, etc. Promos, entrances, move sets, etc, all based on creating predictable and familiar moments.
Essentially WWE is set up as the McDonald's of wrestling. Is the in ring work going to be the highest quality in terms of work rate, Flash, etc? Far from it. But the audience is familiar with it, they know what to expect, etc. No one goes to McDonald's for a gourmet meal, but we all still go there.

It's not necessarily a bad thing. It's just very much built towards a highly casual audience. The majority of their viewers aren't hardcore wrestling fans. Doesn't mean hardcore fans can't enjoy it. I love cooking nice food but I'll gladly go for a big Mac any day of the week.

In terms of adjusting for performers, I think it really means beyond the other factors stated like hard cams, wrestling for tv ie commercials, etc, that they have to really know and be able to sell what makes them recognizable and familiar to a casual audience. Daniel Bryan comes out and they're conditioned to point their fingers and yell yes.

I'm not sure the amount of dangerous gimmick matches that typically get booked in WWE are "responsible." Not to mention how over-worked the roster would get before the pandemic.

The style isnt exclusive to the matches but a lot of time the match order as well. Its supposed to be a roller coaster effect emotion. Its why for years they would sometimes put a 5 minute diva match right before the main event or before two important matches. That would give the crowd a chance to cool down after a long match and the main event, which they obviously want big reactions for.

But I think today its harder because everyone wants to steal the show and the crowd actually reacts louder to something they dont like, burning them out. Then by the big match, they are sitting there waiting for something cool to happen instead of reacting during the heat.