Yeah, you're right. Flame blower can just get you killed instantly, if you're surrounded by zombies, and barely do any remote damage, at that. It only does 5-6 damage, plus he has a giant head. So, when put up against all these high damage, high health, and tiny hitbox zombies, it's a bad situation. I don't know why zombie mains complain about its length, cause it's only viable at a longer range, unless you need to take out an imp in a 1v1, or finish someone off who has basically no health remaining.

As someone that's rank 1000, I can tell you the plants are unbelievably harder to play as, given that they can only rely on their own body and elements of nature alone, for weapons. On the contrary, zombies being human or humanoid, makes every single character on that side, have ultra-powerful, oftentimes fully or semi auto guns, and other military level weaponry and abilities. This makes aiming, shooting, damage, and stealth all significantly easier to do, whereas the plants have harder aiming, way less stealth (in giant head/body cases) and less damage output.

However, you still wanna be a plant on occasion, my advice is to ALWAYS stick by or back behind teammates. That should always be your goal, even if they're all spread out, if you look around you can find 2-3 and that should be enough. If you can't find them, just scout out some good hiding spots and try to stay within range of those, so you can retreat quickly to them. Or if there's no spots, but there are walls, try to get behind the wall to let your health start regeneration or to flank zombies.

But in general, stay back so opponents won't put so much focus on you, and some will focus on your teammates instead. If you wanna help your teammates stay in the fight, be sunflower. Or if you wanna kinda carry them, use a high damage character, whilst staying behind or near your team.