With widow it's not so much the accuracy that counts. Obviously you need accuracy to do anything worthwhile but the 1 shot kills are what really matters
in a game where u can play as a cyborg ninja with a dragon sword and a armored guy swinging with a gigantic hammer or fly around while shooting deadly rockets and a DJ who can wallride and kill people with music or an angle who can bring people back to life and u choose to play a fuking sniper which u can play as in EVERY OTHER FUCKING SHOOTER GAMES but okay!
Jeeez, stop trying to find that perfect time of “when to go to play comp”. Qp and comp are very different, no one gives a shit in qp. Go play comp, and get better there, and stop asking random people “am I ready for comp”
Playing Widow has so many things that change her effectiveness. You can play her in one match that has no shields, no dive, and player that stand around and you'll do amazing. Next match they have Orisa and Rein with a Genji that's constantly focusing you out and you wonder why you aren't doing well. Lots of variables to playing her in ranked. Just pick her and if it's not working swap off EARLY.