Alright. Disregarding the other thread(s) I made while away from this one, and getting more clarity on the speed rules now at this point, MFTL+ reactions should still exist from the travel feat(s) here under these circumstances. I will be ignoring other parts of the discussion right now to address this as the main priority.
First things first, addressing the "prepartion and slowed down" points. This will reiterate brought up points from before, since they were not countered here, but there's evidence to help claim neither of those things happened in this feat to start things off.
Takuto, the one doing this speed feat, did not prepare to do this feat beforehand. His only purpose in possessing Rekka's body was to watch Aichi and Ren's Vanguard battle for himself firsthand.
https://cdn.**********.com/attachments/574596090788315196/898570306455760926/unknown.png?fbclid=IwAR149L7v-yqm5gaudfn8MWm96km6vwTQ1FZFoMFzwyNWuuEeW6LyO9KGdB4
https://cdn.**********.com/attachments/574596090788315196/898570463918292992/unknown.png?fbclid=IwAR1TJJDrgLFfUcAxBobfbTlDHdPHsHVcUHc1tsGsoXV50ghEKmQ_TTVwsIY
https://cdn.**********.com/attachments/574596090788315196/898636988297662464/unknown.png?fbclid=IwAR0a81xp0Sln5bdw5M5EjSPnlEb0BNCK43vCFz92ihsYcnItsRzYAx3K8PQ
https://cdn.**********.com/attachments/574596090788315196/898570574161399818/unknown.png?fbclid=IwAR3DWB8svwgHppLnePXuWh73Yf8_SUhhkgGTTFgiA_HtzLtGmKKepCjdtv4
The second their battle ends, he performs the speed feat and goes to Planet Cray. The clip of the feat has been posted dozens of times here, but I'll post it again.
Spectating the Vanguard match was the literal only demonstrable thing Takuto was present here to do, to see it's outcome. There's demonstrably no instance or implication of preparing to leave for Cray beforehand as dictated in the material shown to us. He came to see the match, saw how it ended, and left. For all intents and purposes, this flight speed was done extremely immediately right off the bat.
Now, as for what happens during the actual flight and it's conclusion, evidence to prove no deceleration or slowing down happened comes from how they arrived onto the planet.
When approaching Cray and coming into the atmosphere, the sheer force of the flight itself tears through and disperses a cloud layer.
https://cdn.**********.com/attachments/574596090788315196/888417057950011412/image0.png?fbclid=IwAR2TByP5U-KOhPklpMxzJhb3D45Vfu1lKgc9cKgChGMwZ_7LEWSQnvoDupI
https://cdn.**********.com/attachments/574596090788315196/898640813700050954/unknown.png?fbclid=IwAR2BTjSb2blbADVegfvBoUr0FfaR7-A16GKfFBxfMWbt-7_6zQqLQ00m61E
https://cdn.**********.com/attachments/574596090788315196/888417061351616563/image0.png?fbclid=IwAR2zZVo-N7pdB-T_tR8gAagmua8LzBuOEKhF2MiM9SR5dlHqDekhkJ5dPbI
https://cdn.**********.com/attachments/574596090788315196/898642488452059186/unknown.png?fbclid=IwAR0Y6XuZDTlCj6CZutG76YqI3eYUMLCv_jZQw9ZUVfd_Dy9i3A-_4mnvr-Q
And in that moment when landing, causes an explosion on the planet (yes, this is being brought back up as well).
https://cdn.**********.com/attachments/574596090788315196/888417078808301588/image0.png?fbclid=IwAR3XJqDA3vBOTkqjIQE4Hi-ZWGGST_8255XRUlgakoI8KhtBVm8NJDeQAw4
Going beyond the simplicity of just saying "they don't show to be slowing down", these details and the effects unleashed by the flight itself indicate there's no deceleration happening prior to the landing. After all, dispersing a layer of clouds just by passing through them, and unleashing force to cause an explosion, implies great force is still being put into the speed. Which can't be the case if they slowed down before the landing was done.
I also reiterate this evidence again because this implies a successful landing was done. Seconds after the feat is finished, we see Takuto and Ultra Rare standing upright, unfatigued and completely fine post-landing.
https://cdn.**********.com/attachments/574596090788315196/898687626016591892/unknown.png?fbclid=IwAR2bOqjT8ISYRR9eBVwRVN23Yivt4OXMOsci0Tdpdhckxm8gZTGmSQ1YoGI
Also, a very strong new point not given before, that can be added to this, is Takuto having perfect control over his flight speed.
Shown here in another universe crossing flight speed feat Takuto's soul performs, he is shown to have stopped himself midair at the end of his flight feat.
By stopping himself midair, it shows Takuto is capable of having control over his flight speed to successfully halt himself when he chooses. Adding this with the above depiction of standing upright, and having no visible harm or fatigue at play, it makes the notion that Takuto can prevent himself from crashing smack-dab into the planet and freely stop himself very reasonable.
On top of that, returning to the cloud layer point from before, the location on Planet Cray that they went to was covered by those clouds, making it preventable from being seen until after they would pass through the cloud layer during the flight.