No.
Opening your Steam Deck will not void the warranty, and your warranty is reasonably clear on what does void it.
In principle if the cause of fault with your steam deck can be proven to not be yours and a fault of manufacture or from purchase, then it is on Valve to fulfil the warranty to repair or replace, or in some countries ultimately refund, your Steam Deck.
The comments about removing labels and voiding warranties hasn't been legal for a long time and precedents were set in many country's laws, especially EU, about that.