the link you provided was for a player drafted in 2019. He had a 5 year deal, not a 5th year option.
The new 5th year option rules came into effect in 2020.
EDIT - I researched, and the rule was adopted 2018, so I was wrong about your example not applying.
Now the question is whether that site has the rule right or not regarding trades. I still think Im right about that, but the rule IS older than I thought. On further research, i was wrong about that.