This is right after Spence taking a throw-in around where he stands. Sarr is searching for an opening, but everybody is either marked or has an opponent running at him that will get there by the time pass reaches its target. You can already see Porro sitting narrow because inverted fullbacks, which will be relevant soon.
This is slightly misleading because it gives the impression that Romero will have all the time in the world after he gets it from Vicario, because you can see a Bournemouth player running right at him.
By the time the pass is made, the said Bournemouth player has already covered a good amount of the distance between himself and Romero. The latter will be in trouble soon.
At this point Romero has two people running at him, and nobody except Bentancur who is trying to make a run wide is even semi-available. All of this stuff is happening in real time obviously, so screenshots always underestimate the difficulty of playing these passes through tight spaces.
Turns out even Bentancur is chased by a player. Johnson, who is also marked by the way, comes out of nowhere to provide an outlet by dropping deep in a hurry but can't execute the relatively difficult one touch pass. Turnover.
Similar scenes a minute later. Romero, not being able to find anybody open, gives it to Bissouma regardless who's under immense pressure. Everybody's easily marked mainly because how close they stand to each other. Porro is once again sitting narrow as instructed, which eliminates a crucial passing option of Romero's.
Bissouma makes a mess of it, and Bournemouth walk into a clear goal scoring opportunity without breaking a sweat. It's that simple.
Same stuff a few minutes later. Romero is once again searching for an open teammate in vain. Porro the RB is nowhere to be seen because he's instructed to bomb forward. Spence the LB sits narrow, which takes another passing option away. Romero gives it to Bentancur regardless, lest he has to hoof it up.
As you can see Bentancur has no other choice but to pass it all the way back to keeper, which I assume is not something the manager would like to see from his players.If he doesn't get tackled that'll allow Bournemouth to get out in transition that is.
Referee comes to the rescue by blowing the whistle, because otherwise Romero and Danso would have got caught in a 2v2 in open space. Just like that.
I didn't even include the first minute giveaway by Romero, as it was an unforced error on his part. This kind of stuff happened over and over again over the course of the match, with Ange standing on the sidelines helplessly. Either Iraola is the biggest genius around, or Ange is extraordinarily incompetent. Take your pick