Hey Neil,
Somehow the html got corrupted when I pasted it into my post above. If you delete the end of that html, you should get this. Which hopefully will work:
https://www.vegascreativesoftware.com/ca/video-editing/how-to-color-grade-videos-like-a-professional
In essence, what you are looking to do is a “Color Key” or “Change to Color” effect – these are stable tools of most video editing software tools. There is nothing amazing to this, except for the expectations of the production.
As I am sure that you’ll recognise, your image would be easier to work with if shot on a Green Screen, and the background added afterwards. However, for total control (perfection), you can mask the foreground, so you either only apply effects to that or the background or both.
But in its basic form, and there are many tutorials on how to do this, you’ll want to pick the color that you are changing, and manipulate the range and intensity of that color only.
This is one slightly older tutorial, but appears to cover it:
https://www.youtube.com/watch?v=ngfR-6t8B3g
In Vegas Pro 20 you should have Boris FX Primatte Studio for advanced chroma keying, which may do the job for you in regard to isolating the colour. In any case, you should spend time getting to know that plugin really well.
If you have the finance, you whould also investigate BorisFX Continuum suite – comes with a free trial, and you can subscribe on a monthly basis which will allow you to use it as a pay-as-you-go.
If you really want to get deeper into your finishing, the Blackmagic Davinci (with Resolve and Fusion) is currently the best game in town, which starts from free. Or as you are making reference to Photoshop, you could take up After Effects (also comes with a monthly plan).
But, regardless, there is no easy quick solution to your question, as every piece of video and image is different. And, you can easily spend hours on just one piece of video, for just at the end of it, you are the only one who will notice the difference.
Hope that this helps.
Atb
Mads