Yet other vehicles at its BR get by with less penetration.
You can’t fire the LOSAT while moving. Even with the extra acceleration there is no guarantee you will reach a position you can begin firing from due to the lack of a stabilizer / gun depression / the missile’s mechanics. All of this makes the speed advantage irrelevant.
Not every vehicle can be the fastest, the LOSAT isn’t the fastest vehicle even at 9.3
Yes quite. If the 775 had access to APFSDS with its armor and profile I would think a BR of 10.3 or higher would be justified. As it has a rather mediocre ATGM it survives quite well at 9.3 with other ATGM carriers of its BR range.