The first line in your post is:
Is there any programmable or configurable box that does "switching" at
the physical level?
That is either a question seeking a Yes/No answer, which is a bad question, or you are asking for a product. Questions like that really are not suitable for SE sites (other than Hardware Recommendations).
Your other question is:
What do vendors, like Cisco, Arista, and so on, do in their LABs to
decrease physical intervention for changing topology?
That is something you would need to ask each company because each can do it differently. We really cannot speak for other companies.
(I can tell you in my personal experience with our company traveling to Cisco for testing, the Cisco engineers are very disciplined and manually make changes. They rack the test devices and use the cable management attached to the racks. There is no cable mess because they take the time to do it right in the lab.)