Here’s a good comparison article. The one thing missing in the article is availability. Tesla‘s truck is expected about one year later than Rivian’s.
Tesla Cybertruck vs. 2021 Rivian R1T: Electric Trucks Compared - MotorTrend - Motor Trend
Tesla Cybertruck vs. 2021 Rivian R1T: Electric Trucks Compared - MotorTrend - Motor Trend