again we have an established rule set for the Uchihas
Boruto is a new rulebook since we don't know what KKG abilities he has let alone his new dojutsu
to say it is the same thing is not true since we don't know what powers allows Boruto to do things
the rulebook never said feats were exclusive to tomoe, tomoe only represent an upgrade in dojutsu strength but the dojutsu itself relies on the person's Yin affinity and chakra quality.
Itachi without 3 tomoe was already better with kunai than pretty much every Uchiha, Sasuke without 3 tomoe was able to read Haku's shunshin and Lee's shunshin, without MS was able to break Tsukuyomi and perfect element jutsu, Orochimaru even claimed Sasuke's eye power surpassed Itachi's before he even awakened the Sharingan.
See what I'm saying ? Sarada got her eye power from the guy with the strongest eyes in NV, she inherited his spiritual energy and a portion of his chakra, by logical standards her dojutsu already surpasses the average Uchiha which is why she can do feats beyond her level.
She's not the first Uchiha to do something like this which is why your statement on the rulebook isn't quite right.
With her chakra and Yin affinity her eye power is much stronger than the average Uchiha regardless of the number of tomoe she has, this is emphasized by Kishi giving her the bad vision only MS users are known to have.