stress relieving cnc frame

Hi, my name is Farzad and I am from Iran.
I am building a DIY CNC machine for myself, and my goal is to make money with it.
I designed it in SolidWorks and bought the necessary items (I also made some purchasing mistakes).
This is my design (it’s mostly inspired by a YouTube channel not an engineer).
The design is simple and is made from a 250mm × 250mm × 1300mm iron box with 8mm thickness. The material is called ST37. I am going to reinforce it with some + shaped plates and weld them inside the iron box.
For the linear rail placement, I bought some 35mm ST37 plates that I am going to attach to the main iron box using bolts and epoxy.
These plates were cut from a very large plate with a torch.
Stress relieving these parts is costly in heat treatment furnaces.
Can I use VSR instead of an oven?

I asked ChatGPT about it, and it suggested that I can grind off the torch-cut areas first and then use VSR on them, because most of the residual stress is concentrated on those cut edges.