I look at this account, I see the match history. This person has never one-tricked in their life, suddenly after barely playing for 3 weeks (letalone months, they rarely play multiple games, and played under 50 games in 2018) suddenly, they hop on Vayne/Jinx, spam it for 19 games with absurd KDAs.
Nah. This doesn't look like the same person, if it is, they definitely changed for 1 day somehow.
If you look at my match history, you'll see I have absurd Skarner top lane games, but you'd also notice I consistently spam a champion for 10-20 games in a row. Did it with Ornn, Skarner, Nami, and Tahm Kench recently. That person, RARELY played a champ 2 games in a row. rarely played in 2018/2019 suddenly play a shitload in 2 days with an extremely high win rate.
I'm no marine biologist, but I think that behaviour is pretty fishy. If it's not scripting, it's a bought account.