They were possibly private military contractors and not S.H.I.E.L.D agents
In Season 4: Episode 22 "World's End", after everything that happened with Aida and the Framework, Fitz decided to turn himself in as Mack tells everyone that the authorities were coming for them.
Mack: We picked up radio chatter on the Zephyr. The good news is, is that Talbot is alive. He's in a coma, but alive. The bad news is they know we're here, - and they're on their way.
Fitz: Yeah, you should go while you can.
Daisy: Yeah, we're all going.
Fitz: No, I'm gonna stay. This is my fault Aida, the LMDs, all the deaths. Those aren't on S.H.I.E.L.D. Those are on me. And, uh, I can explain that I built the LMD that shot Talbot.
So Enoch could have disguised himself as the agent in-charge of capturing Fitz and others thereby gaining access to Coulson and team for the mission.
But a few things contradict this. Firstly, listen to the conversation between the two soldiers outside. One of them actually says
Soldier: Haven't done one of these in a while.
You? My wife thinks that I'm at a friend's house for our fantasy draft.
Doesn't even occur to her that we're in the middle of the season.
Doesn't even occur her.
Their formations and techniques show some sort of trained military sense in them. But this conversation tells that their families don't know what they actually do.
Soldier: We left one sitting at the counter, sir.
Enoch: Yeah. Not on the list.
If they were actual agents, they would have taken all of them specifically Fitz as he was the prime target; however he's the only one they leave behind. Since Enoch tells he's not on the list.
Thirdly, in the beginning, we see Enoch renting into a shady van with fake logo on it. As far as we have seen across the series (and also the MCU movies where S.H.I.E.L.D was involved), S.H.I.E.L.D uses its own transport at all times.
So, it looks like Enoch hired some contractors to capture Coulson and the team for his mission.
PS: It has been established that such contractors already exist in MCU. Billy Russo, for example, in the Netflix series Punisher, owns such a company called ANVIL that has ex-military personnel who can be hired for various jobs.