how do i beat syndra...

A pretty good strategy that many people started using is banning her lul Other than that and mages that outrange her like maybe have a good win rate against her.

if shes good enough you don't. literally every good syndra i play against has 80%+ winrate on that champion. she needs to be disabled

There's a few ways to win that matchup. Squishy champions suffer very heavily to her early game and level 6 powerspike. Rod of ages/negatron first back are a very strong build path vs syndra. Barrier also helps.

Dodge her q's early on in the laning phase and you'll be fine. Also remember if you're a champion that can rush zhonyas rush it and when you see her ult zhonyas and her ult will go through and do no damage. The counter to syndra is don't give her a lead early really.

Assassins are really good vs Syndra. But sadly Assassins are also terrible in this meta, so your best bet is to just ban her and not deal with it.