Preschool Halmahara taming

[Fledgling]

I've recently taken over the care of the Bluey in a 3-year-old classroom of the preschool I teach at. Unsure of sex, around a year old. They have not been handled much at all, huffs every time I go into the tank, strikes when I have to be within a foot of them. 3-year-olds are high traffic by definition, so not much I can do about that stressor.

My goal is to get them tame enough to come out for enrichment and/or playpen time. Due to licensing, children are not allowed to touch any reptiles.

Before the spring I had started holding them over the tank for short periods, but then instead of just huffing at me, they started to strike too. The strikes appear to be more warnings than true attempts to bite, but I've backed off nonetheless. They were in a tank that was much too small at the time, so I figured that they were feeling cornered and chose to hold off on taming until they could be upgraded.

We recently upgraded them to a 75 gal tank (while I search for an appropriate 4x2x2 at a preschool price...) which has lessened some of their defensiveness. I've also put cardboard on the sides of the tank to help them feel more secure. Now they spend most of their time in their warm hide, but can also be found under the water dish on occasion. When I go to change the water, they huff, slink off, and will sometimes strike when I put the dish back down or pour the water in. He only appears to venture out immediately after I put down the food dish, and only until the children notice he's out. Once he sees them, he goes back to hide.

Now that it's been a couple months since his tank upgrade I want to start working with them again. I read the taming post, but given the specific challenges of a preschool environment I'm unsure of how best to proceed...

Any insights? This is the first Bluey I've cared for in the long term as I worked in a small local pet store before teaching here. While we prided ourselves on hobby-level care and knowledge in the store, our Blueys would only be with us for a couple months at most.