2019 Tacoma SR issues help!

My recently purchased 2019 Tacoma SR has only 30 thousand miles on it. There is a Bogging Shuddering vibration I feel through the truck at about 3rd 4th gear between 45- 60 MPH it sounds and feels like I am driving in too high of a gear like it should be downshifting along with the shuddering! I also am experiencing a whistle sound as the truck shifts into a higher gear when I do try to pick up speed! These issues seem to be most noticeable after the truck has been driven and is warmed up. Toyota says this is just a characteristic... this is Not! My father in law has the same truck... no issues

 

It's good you have a comparison vehicle. I would start with the dealer: have them show you a comparable vehicle on their lot then drive each one back to back.
If they don't accommodate you, open up a case with Corporate then find another dealer. Hopefully another dealer isn't too far away.
As a last resort: replace your WS ATF. My son's used 30k Taco had brown fluid, we replaced it with 2 drain/fills.
Point being one doesn't know your truck's past history.

Good luck.