Why do I have to type .exe after all commands in windows 10?
It's possible that your %PathExt% environment variable has garbage in it – it's how cmd.exe knows which file extensions it should try. Normally its contents should be:
C:\Users\Mantas>set pathext
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
Use sysdm.cpl → Advanced → Environment Variables to check and fix it.