Repeating letters when typing

The sounds like an issue with the MBP Butterfly keyboard. I’ve had this issue myself twice. Apple will replace the top case of your MacBook for free if it’s one of the affected models. (Which is every model of Mac that has the butterfly keyboard).

See if you qualify here:

https://support.apple.com/keyboard-service-program-for-mac-notebooks

Make an appointment for a "hardware issue"—

https://www.apple.com/retail/geniusbar/