In fact, if we consider that this is a limiter, that is, no one less durable than the Base Raikage can move at this speed, That would also be a support for him, wouldn't it? because he base resists transfer, which means that his body supports the speed, and we have the statement that equates him to Minato in Yoroi lvl 1, and the Lariat statement, everything corroborates the fact that we have the base Raikage Rel/Rel+, SoL with Yoroi lvl 1, and FTL with Yoroi lvl 2+Shunshin. The cases of Haku and the character from the novel Retsuden can be treated as exceptions, as they are also having a boost by a jutsu but which has a different method.