It sound like we have a similar coop set-up. The first week was rough for me, too. I had to corner and herd them into the coop/run, then catch & place them individually into the house, & then close the sliding wooden door to keep them in for the night. I never did the 3 day lock-in method, so that is probably why I struggled.
Two things I eventually figured out to get my chicks going to bed on their own without needing to close the slide-door: 1) develop a regular bedtime routine involving food and using the same verbal cues, and 2) use a light to lure them in.
I always enter the coop the same way as dusk approaches, then feed and treat my hens, so they are full and ready for bed. Then I turn a small plant light on in the coop. It works like a charm. One by one they enter the run and after about 10 min of pecking order decision-making over who goes up the ladder 1st, 2nd... they eventually climb up & go inside on their own. Once everyone has had a few minutes to scratch the bedding & get settled, the light goes off & all goes quiet.
The biggest change I made, though, was with the coop. Most pre-fab coops use flimsy, inclined ladders with open rungs, which causes slipping & fear. To fix this issue, I bought rubber stair traction at Home Depot ($2 worth) and cut it to fit each rung for better traction and also to visually close the opening between rungs. It's still a flimsy ladder vs a more gradual & secure ramp, but it looks & feels safer to them, so now they are not afraid to climb it. I did need to place them on it and help them up initially, but it only took a day or two before they were all using it without any help.
Good luck!