I have 2 fully flighted Bourkes and they came to me clipped - but they were older juveniles and could fly a little. Anyway, I did tame them and they now fly just fine. Don't worry about yours - he will learn to fly in time. Just handle him a lot and by the time he gets his "wings" back, he will be very bonded to you.
My Bourke Parakeet named "Twitter" - shown here fully flighted.
I also have a Scarlet Chested. Mine was not really hand-raised sufficiently (only for a few days) and came to me upclipped. I never clipped him but unfortunately, he never got very tame. He flies around my house OK and will occasionally land on my arm or the back of my chair, but he is afraid to perch on my finger. I think Scarlet Chesteds are harder to tame than Bourkes so you might want to clip your new baby and also let his wing feathers grow out too, like your Bourkes.
My current Scarlet Chested "Elvin" - he was never clipped but also never became really tame.
Previously, I had another Scarlet Chested that was clipped and I was able to tame him. By the time his feathers grew in and he could fly, he was tame and would fly to me. So one initial clip isn't necessarily a bad thing - especially for a Scarlet Chested.
My first Scarlet Chested - "Peeper". He was a great pet but unfortunately got Proventricular Dilation Disease which was fatal.
I will say this, however. While an initial clip can help with taming, birds that are never clipped fly better and have fewer accidents. My current "never clipped" Scarlet Chested flies beautifully and skillfully. My earlier Scarlet Chested (that was initially clipped) had a lot of crashes while his wing feathers were growing back. He did ultimately learn to fly OK but I definitely think never-clipped birds have fewer accidents. Both my Bourkes now fly very well now.
Although I am not pro-clipping and prefer fully flighted birds, I think you might want to have your Scarlet Chested clipped once when you get him so he will be easier to tame and be in the same boat as your Bourkes. By the time their wing feathers grow in and they can fly, they will be fully tame. Just be careful, while they are learning to fly.
Both my Bourkes and Scarlet Chested like me to lay on the floor with them. I put a millet spray in front of me and they fly down to eat it.