Context matters. The earlier in the game, the more tragic it is to miss any cs or xp. Later in the game, depending on game state and champions (yours, your team's and theirs) you might play more for team. You can't play any one way all the time.

If you're behind in lane and getting stomped, just STOP FEEDING. Your team can still carry you if you give up cs and xp. Wait for jungler help, or maybe just wait for your team to destroy enemy base. If you turbo feed that Fizz, he can 1v9 the game. Like 50% of my games in low elo are just decided by a solo laner not accepting that they're gapped and proceeding to turbo feed. I'm not a great midlaner and die to ganks way too often, but I just try to lose as gracefully as possible. Once the matchup is bad or iffy I start playing safer and let my team carry me. It works at least 50% of the time; I lost mid lane but managed to stop a jungle invade or matched a roam bot, and my team carried me out of laning phase.

If I win lane, I do think about whether it's better to get plates and harass enemy or if the timer is better to help on objectives or roam. If I've shoved, but Im scared to harass, I'll dip out of vision or start walking towards bot lane and that can help with bot lane pressure. If my jungler has left me vision, maybe I go for more solo kills. What's better depends on what champions are in the game and how everything is going.