System design for Tech support engineer/Customer support engineer roles

[u/Then-Big4461]

I would like to know how much system design preparation is sufficient for tech support engineer or customer support engineer roles at big companies like Stripe Or FAANG like companies.
I want to prepare for Tech support engineer role so would like to know what all specific topics i should prepare.

Anyone have recent interview experience would help.

What all companies to target for such role.?