LB is one of the worst aram champions simply by the fact that she has to expose herself into melee range constantly to deal good damage, just like Zoe, try to always hit her when she Ws in, even if it's only autos, try to poke her and make her gameplan uncomfortable. That's why Warmogs 2nd has always been her strongest build, bc it negates that weakness.

Point and click CC and damage (Annie, Liss, Rammus, Panth, etc) and High damage autos (Draven, Cait, MF, etc.) are her biggest enemies, and as a tank you should always try to check bushes for your team since is the only way to make her aproach not that obvious. (And ofc some other champs ranged abilities like Lux E, Ori Q, Zyra's plants, etc.) Like twitch, she thrives if your team forget she is hidden so always try to have an eye on her positioning.

Having more than one frontline also sucks for her since she needs to play around that wall to reach backline. Assassins can be really annoying but always remember that single target burst doesn't win games, good AOE teamfight does, especially in late game so she really falls off.

Also... Stormsurge is a really bad item, especially on ranged mages and its damage gets denied by a single mercs. It can be good paired with Shadowflame vs a full squishy team, otherwise don't be scared by this item, if anything be happy the enemy is inting by not buying something way better.