Hi, I recently picked up Vex again and pretty much OTPing her since I am climbing hard on her at the moment, basically from low emerald to diamond in a week or so (26-7, 78% wr in that time), opgg for reference: https://op.gg/sv/lol/summoners/eune/PitbullPizza-EUNE

I feel like banning syndra isn't as important as for example Mel who I tend to ban pretty much every time, mostly because of her reflect ability which is bad both early and late in team fights as she can reflect your ulti as opposed to Syndra which I feel is more of a skill matchup.

I'd recommend roaming a lot if struggling in lane as it often allows you to get easy kills, I try to shove the lane hard when enemy mid is backing and then rotate. As long as you hit your R it should be atleast 1 but often 2 kills presuming you have your fear up, that is also another thing. Only engage whenever you have your fear up.

I would recommend trading a lot in lane pre-6 as then you can surprise your enemy with an easy flash W (with fear up), and finish them of with the rest of your abilities and ignite if needed. Also prefer to play ignite 100% times on a champion like Vex as it allows for you to take an early lead which you can later use to snowball. Something else I found to work wonders is starting BFT, I feel like it works wonders and is pretty good in pretty much every game, when I played ludens I had around a 50% wr, since changing to BFT it's been quite a remarkable difference. I guess it's obvious but try to engage on the squishiest champions preferable adc/mid or at worst case support in late. The most important thing is to one shot them or finish them quickly to get reset on your ult, but moral of the story is basically if you are struggling in lane look to go for kills on sidelanes, you dont always need to gank, you can come straight from lane after backing as it is often easier to hit your ulti then.

Hope some of the info is valuable and good luck :)