yeah see I really don't believe that. Unreal engine is one of the most used tool sets for all kinds of different games. It's one of the most well documented engines for game development. It's easy to use and a very flexible tool. Rocket league started out as a mod for unreal tournament. You can go to their website now and download the basic kit, just as you can with the Unity engine.
Modability is up to how the game developers are putting their project together. not which engine they use.
Check out Shadow Tech, it's essentially an App that lets you have your own gaming system on your computer. It's $12 bucks a month for the starter pack, but worth it if you're looking to play games like Skater XL that are only available on PC right now. I have an iMac and play Skater XL on it almost daily, can't tell any difference with graphics or performance either.
My motherboard has bluetooth built in, but you can use a dongle like this.
https://smile.amazon.com/Bluetooth-Receiver-Keyboards-Controllers-USB-BT400/dp/B00DJ83070/ref=sr_1_5?dchild=1&keywords=bluetooth+dongle&qid=1627511452&sr=8-5
I'm just using one from Amazon... pretty sure it's this
If you don't mind a wired controller the PowerA Pro Xbox controller works well. It has been great for me on PC. There's a cheaper PowerA option that I haven't tried. https://www.amazon.com/PowerA-Fusion-Pro-Wired-Controller-Xbox/dp/B07XQXQMR9/ref=mp_s_a_1_2?dchild=1&keywords=powera+xbox+one+controller&qid=1594857129&sprefix=powera+&sr=8-2