Samsung DeX is described as '("Desktop eXperience") is an accessory sold first with Samsung Galaxy S8 and S8+ devices that extends the functionality to allow desktop-like functionality by connecting a keyboard, mouse, and monitor' and is an app in the Network & Admin category. There are more than 10 alternatives to Samsung DeX for a variety of platforms, including Windows, Android, Mac, iPhone and Android Tablet. The best alternative is scrcpy, which is both free and Open Source. Other great apps like Samsung DeX are AirDroid (Freemium), Vysor (Freemium), ApowerMirror (Paid) and Wormhole - Control Phone from PC (Freemium).
ApowerMirror is a wireless screen mirroring app that allows fluent streaming of your Android or iOS devices to any Mac or Windows computer. It can also control Android devices from PC with mouse and keyboard.
Mirroid is a phone mirroring and control software allows users to mirror their phones on the computer and control the phone with computer. It can be used in a working scenario and play mobile games on the computer.
Wondershare MirrorGo is a useful tool that could mirror your android phone screen to the computer. You can get all the notifications from the phones with the PC. You could use it to record phone screen, play phone games with mouse and transfer files.
Dell Mobile Connect provides a complete and wireless integration between smartphones and PCs. The (gigantic) downside is that it can only be used in newer Dell PCs. You can send SMSs, mirror screen, and more