I only play Garen so i don't know if its the matchup but I don't remember the last time i've won vs Gangplank, I always manage to kill him twice in lane phase and not die but he always stays relevant in farm, and becomes this monster late game
So how am I supposed to deal with Gangplank or should i just be banning him every game
Gangplank is not a great late game champion, but his kit ensures he gets there before everyone else. His early game is abysmal; His teleport ganks are really poor and he can't deal with all ins. Instead of trying to shut him down, instead try to snowball your other lanes. All gangplank wants to do is sit on his barrels, farm, get his bandit gold from Qing you, and occasionally ult another lane to pick up some extra gold.
It's really hard to shut him down, especially as someone like Garen because he can farm from a pretty great range, and he gets extra gold from just about everything. Instead, focus on early objectives, and if he drags the game out to the point where he gets his 6th item while everyone else is working on their 5th, just remember, he's not get any stronger.
All this is assuming you know how to teamfight against him. If not, focus on learning that first before focusing on beating him on a macro level.
Gangplank is good at kiting, garen is weak to being kited.
1v1 this is a matchup you are going to lose unfortunately, best advice i can give is build early armor let him push lane while trying to prevent him from roaming and ask for jg ganks and mid roams to top, GP is fairly immobile and relies on slow from his barrels/ ult to kite, if he gets locked down by a jg chances are he's gonna die.
Play someone who scales better than Garen. Yasuo v gp is good, and Darius is still a better pick than Garen in that matchup. Sion can also hold in that lane, and if you go full tank, Gp does no damage to you mid- early late.
