Good online games on steam without hackers ruining all matches

Maybe set your library to public, so we can suggest games to you that you already own.

In this game you can kill people with kindness.

Have you tried to play PUBG? I've heard it's a fun p2p

Fortnite?
hides from epic-haters

Look for TF2 servers labeled as "VAC secured" and any servers running Sourcemod and you'll likely see less hackers.

As far for competitive games, I can recomend you Dota. It does have hackers, maybe 1 in 5 to 10 games, but playing against them is not instatly lost game like in fps games. You can build your hero to negatate their cheat combos, and that is actually fun part of those games.
Community usually gathers on reddit, and it's very active. Patches for game are regular (these days there is small patch every day ~50MB) - there is good and bad in that, good because game is more polished every day and bad only if you're on metered connection. Within month there should come out batttle pass (hopefully, it's yearly event but we'll see considering covid crap how it goes this year..) which will provide some sort of quests and more. You can always check out how the game looks on twitch, and see if that is something you could like. For a noob only thing that might turn you away is matchmaking, there are a lot of smurfs (old players who know game mechanic playing on new accounts) but if you can go past that you'll have fun (don't hesitate to use mute button when people start to complain on how much you suck :) )
Game is completely free (except optional battle pass); only limitation you have is for first 20 (?) games when you have limited hero pool (you can disable that in console if that is something you don't like)

The sad truth is all online games have cheaters / hackers. The good news is if the developers care they work to keep it to a minimum. Like Apex Legends which besides banning, pairs cheaters with other cheaters so those who play fair can enjoy the game.
I recommend Steam Valve anti-cheat games because once you are caught cheating on a VAC game you are banned for life, unless you create a new account. So there its considerably less than games by developers that use it as a selling point e.g GTA Online, or Minion masters that still has no way to report cheaters after all there years.

As for specific games, try Apex for free if you haven't already.

https://store.steampowered.com/app/270450/Robot_RollerDerby_Disco_Dodgeball/
This game was a great dodgeball game few years ago and I never seen any hacker. We weren't a lot playing this game some years ago (like 70 or so online when I was playing),it was quite friendly and it really was a blast. I don't know if there's still enough player to play right now or if it's dead so if you already have the game you can try it, otherwise I don't think it's worth paying for the game

https://store.steampowered.com/app/444090/Paladins/
I also played Paladins a lot and I only see few hackers the early days. To be honest you will only see that kind of cheater at low elo games, when I stopped playing I was top #50 world on "onslaught" gamemode and #2000 world on "siege" gamemode and I only see like 15 to 20 verified hackers while grinding elo for many hours. (But I saw a lot of "pro" players and it was always fun to destroy them when they were live on Twitch x) ). It was a great game few years ago

Guns of Icarus Online

Perhaps it is not true, but the answer might be: any MP game which isn't a shooter/battle royale/survival.

I not playing many MP games, but I think I never saw any cheaters on Armello or Card Hunter or Shellshock Live. I think that's all I played in PVP.

The best way to avoid cheaters is to play a game based on developer server hosting and not hosted by a user AND it is not F2P, as cheaters just need to create a new account to return, but if the game costs money then they need to buy it again.

Warframe and Paladins would be your best best if you're into shooters with abilities