I have changed my Tundra transmission fluid and I will continue to do so.
It's more complex than older transmissions, but not difficult.
I bought a Motive Products- PowerfillPro and Power Extractor- 2 Gallon (1745) to make it easier to add fluid, which goes in a port on the side.
Basically, the Toyota TSB has you do the following: drain the pan, drop the pan, change the filter, reinstall the pan, bypass the thermostat, disconnect the return line form the cooler, add 4 quarts, idle the engine (and bump it through PRND) until you've pumped out 4 quarts, shut it off, repeat that two more times.
Then, reconnect the return line and set the fluid level: warm the transmission by idling until the fluid temp is between 118 and 133F, then open the level check plug. If fluid dribbles out, let it dribble for a bit, when it stops, you're good. If nothing, or very little, dribbles out, then add 1/2 quart and check again.
More detail here:
https://www.tundratalk.net/threads/5-7-tundra-diy-transmission-fluid-change.106946/
It's Toyota's own procedure for a cooler line fluid exchange. You should be confident that it's fine for your truck.
Worked fine for mine. I used AMSOIL Signature Series Fuel Efficient. Transmission shifts great.