Do oem computers generally have issues when a motherboard is replaced?

I bought a Dell back in March, and I bought the express service contract too lol…

Now it seems the motherboard was defective. They are supposedly sending a tech by with a replacement.

I think they owe me a totally new machine. I think my machine is a complete lemon

What do you think?

I keep having kernel power errors and the computer constantly flashes on and off. There remote diagnostic decided I need new motherboard.

But the dell tech was kind of a doof and mumbled “sometimes when you replace a motherboard other issue spring up”

What was he talking about and how do I argue dell owes me a new computer?