Mac startup key combinations not working?

Ive tried upgrading the RAM and the SSD of my 2012 MacBook Pro, running MacOS Catalina.

When I use the SSD the only option I have is to put the computer into internet recovery mode us OPTION + COMMAND + R. After the recovery mode has load I get the prohibitory symbol and can't get to dial utility!

When I press command + R - it does nothing and tries to start up as normal.

I tried resetting the NVRAM with command + option + P+ R - again this does NOT restart the computer during startup as it's suppose to.

I tried installing Macos on a USB drive but when I press option during startup- it tries to startup as normal.

I tried all the steps above with a USB keyboard but still haven't to.

If I out in the old drive, I am able to start the computer normally. I used disk utility to erase my SSD (Macos extended journal format) and still the prohibitory symbol appears.

A lot of forums suggest resetting NVRAM to solve my issue but, as shown above, I'm not able to.

Please help, I have been trying for 3 days and desperate to fix this.

Not sure if I'm able to take this to an apple store as it's around 10 years old and I've upgraded parts myself.