OS X has shortcuts for commonly used Menu items, just like Windows.
How did you handle mouse driven drop down menus in Windows, might I ask?
And, for the most part, the shortcut keys are standardised across all apps.
And, if you are new to the Mac and OS X, you will have to learn these shortcuts the same way you did for Windows.
Now for individual applications, this is another story as each application will have its own set of shortcuts keys setup by the developer/s of the app/s in use.
So, putting application keyboard shortcuts to memory will be even more challenging for you.
There are only certain applications I use all the time and I have put most of those application keyboard shortcuts to memory over time.
But no one s going to remember application shortcuts for each and every application on their Macs.
This is NO different in Windows.
So, I fail to see you complaint here other than the fact with OS X you will have to learn OS X commonly used shortcut keys that maybe different from the ones in Windows that maybe you have learned to use and memorised for years and years.
Here is a list from Apple of all the commonly used keyboard shortcuts if you care to start learning them instead of using a mouse.
Not every user knows every Mac or Mac app keyboard shortcut, but there are quite a few you should learn using your mnemonics to put to memory.
https://support.apple.com/en-us/HT201236
Leave these up in an active window on your computer or print these pages out for your reference.
Just like all of us Mac users here, it is going to take you time to learn the really most commomly useful shortcuts to get around the Mac OS and applications
Good Luck to You!