I looked into A LOT of guides and stuff surrounding Harbor the past week, and played him a bit past 3-4 hours, and I now started to play him exactly opposite of whats recommended. But in guides play him slow, use lineups for the cove and focusing on using all his abilities at the start of the round.

From what I can see, playing him slow.. is impossible. Playing Harbor the same way you play other controllers doesn't work. The moment "round start" happens you are instantly meant to throw out your wall, run in as you control it, and then use your wave as a push you to the location you need.

His wall has lower CD than Kayo's knife, so spamming it should be needed, you can get 3 walls up in 1 round.

The most obvious mistake people do on guides with Harbor is telling them the Cove sphere is a smoke. It lasts for 3 seconds top in actual round and you can only use it once, its best at taking control over a start, like Ascent B site, throw it down and you got your entire team on the site with 0 dmg taken. Or using it as a fake to plant the spike in. Players expect you to be in the sphere when you play, but they won't know until they get shot in the back.

But all in all, as a Harbor if you Don't get a spike down with the 8 seconds after you used your abilities. Then you are screwed and other controllers are taking full advantage of you.

TLDR: Play Harbor as a Initiator who has smokes. Get your team in on site within 8 seconds after using your wall, or else you lost your advantage as a aggressive controller