The reason Sasuke doesn't use that power is probably the same reason Naruto doesn't use some of his power. The different is less people claim Sasuke has lost his power.
Absorption jutsu has one huge weaken, the absorption speed. Absorption jutsu can't absorb all jutsu/chakra in an instant -
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Kaguya absorbed the jutsu, but it took time to absorb it all. So if an absorption jutsu user tries to absorb a large power jutsu which has a very fast attack frequency the user will be damaged before that can absorb all of the jutsu/chakra.
That's the reason Madara decided to try to evade Naruto's LRS instead of absorbing it -
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That's the reason Kaguya couldn't all of Naruto tail beast RS -
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