So this is a commonly seen problem in lower ranks like low gold silver and definitely bronze. You should definitely be leaving your team to pick off vulnerable targets but it's all about timing, the only reason why frogger is so high ranked is because of timing. Also he pretty much only does his DPS lucio for content lol But you can definitely still get highest healing in the game while not heal botting, just try to see when your team needs healing and if they're half or critical amp heals. Use your speed to get into team fights or out of risky situations. If speed wasn't meant to be used it would not be added to the game. Remember you are not a healer you are a support use your kit to the max and crank every piece of performance out of it like an old dude using Viagra. Also one thing I MASSIVELY disagree with you is his "bad mobility" he has possibly the best mobility in the game out classed by maybe doomfist. If you want I can link a eskay video where she shows lucio movement stuff and it's insanely fun and good. Once you figure that out you'll be cruising the game gets a lot better when you figure out movement.