Despite Satoshi has changes in character between XYZ and SM, there's one certain thing that remained with him in Isshu, Kalos and Alola - 'daijoubu, daijoubu' - the Hikari's catchphrase with her context of being actually 'dajoubu janai'.
At first Satoshi used it to support Hikari, but since the final DP episode it has been his trait for a very long time.
As I said, in DP 191 we had Satoshi using 'daijoubu, daijoubu' for himself after he fell down the stairs at Hikari's home and Hikari asked him if he was fine.
In BW 013 Satoshi fell down from a tree and immediately after that answered to his Pikachu's concern with 'daijoubu, daijoubu'.
Satoshi replied to Serena with Hikari's 'daijoubu, daijoubu' twice (in XY 042 it was at Serena's criticism of being 'the clumsiest one' and in XY 115 it was at Serena's fear of him catching a cold before he sneezed). Shockingly Hikari's bit alongside the memory of the certain Pochama still lived in his mind through Serena's crush and her attempts to get his love.
And even more shockingly, the Hikari's 'daijoubu, daijoubu' bit has survived the Serena's attempts and was used by Satoshi two more times in Alola - in SM 024 (as a reply to his classmates' concern before his presentation) and in SM 085 (as a reply to Mamane's concern after he crashed into the vaulting box).
There was one more 'daijoubu, daijoubu' with the same context from Mao in SM 018, but since we know that Satoshi spammed it sometimes, you can't strike out a possibility that she got 'infected' with it from Satoshi like Koharu got 'infected' from Hikari in JN 075.
To sum it up, it is a fact that Hikari influenced Satoshi so much that he has got not only the countershield idea from her, but her catchphrase which has become a constant part of his personality - and this is something unique.