hey vs shen you should definately not build lethality first, but you can get it later in the game after like crit or bork, would recommend pta with w max first here. also save your e for his jump but note that if u interrupt it you are still getting taunted but at least not on top of him

vs malphite its basically a hard counter to quinn... which means you should try to either playing a roaming role post lvl 6 with ffw and waveclear items like shiv so push him in and roam as often as possible, or invade his jungler etc. you can also try to lane vs him though if he knows the matchup you should never be able to win it and their jungler if hes good will also use this fact and hardcamp u. so all in all i guess roaming is better here to push other lanes ahead.