A quick explanation about why S9 feels so bad to play

A lot of people are clearly struggling with Season 9, and one of the main reasons why is there's a key paradigm shift here in terms of how you have to think about the game as a whole.

In general, with hero shooters, you cannot outdamage the amount the healers can heal in most cases. This is why everyone will tell you that if you're just sitting there putting damage into a tank, you're wasting your time. Between the tank's damage mitigation abilities and the healing from the healers, you'll simply never make any progress. As a DPS player, you have to take off-angles to pressure the supports or secure picks onto the enemy DPS players to create opportunities for your team to snowball and win that teamfight.

This is no longer the case.

The level of damage in the game has been increased so drastically without any similar increase to sustain or healing that you now absolutely can just shred tanks in seconds without caring one bit about the enemy healers. This completely changes the way you have to play the game. As a tank player, you can't simply focus on drawing enemy attention because you'll just die. As a healer, you can't just focus on healing the tank because it won't be enough. You now have to use cover much more than before and learn to disengage from fights if you get low on health, even as a tank. And you can't simply focus on outlasting the enemy team anymore, you have to make sure you're quickly securing eliminations or at least forcing them to disengage because shutting down the enemy damage is the only way you're going to stay alive.

Beyond this, the new team-up system has drastically altered the game balance and there are huge winners and losers. Many previously good characters are now terrible and if you have one of them on your team you're now basically down a player, so it will feel bad. Even among characters who are usable, at least half of them have one teamup that's massively superior to the other, so if you have a teammate who's using the wrong teamup you're also basically down a player, resulting in extremely one-sided matches. This will stabilize as players learn what's good over the next few days, and hopefully they'll make balance adjustments to help out the characters with lousy teamups.

Either way, though, you can't play the game as though it's still Season 8.5, because it's not. Your entire team is just going to get melted over and over until you change the way you approach the game.