Phone bootloop - sending to LG for repair

My Nexus 5X just started boot looping recently. I called LG and they said they would replace the motherboard if I sent the phone to them.

Does LG have the capability to decrypt the phone? I know the encryption is software based on Nexus 5X with a TrustZone based system which could allow the manufacturer to decrypt the phone.

I am concerned because all my banking and tax return information for the last 2 years is on the phone.

I am just trying to understand what data technically LG could...

Phone bootloop - sending to LG for repair