[Ethereum] Cannot install truffle. Node.js and npm are installed

I currently have

node 12.21.0 + npm 6.14.41 + macos big sur 11.2.1 + ganache 2.5.4 + command line for xtools 12.4

I read online that truffle does not support node v13, so i uninstalled the one i had (v15 or sthing) and switched to version 12.21.1.

The latest npm and node installations were done from their website (pkg files), not brew, because i do not know how to NOT install the latest versions with brew.

Here's 2 screenshots of attempt #1:

and

Here's attempt #2

I have been looking for an answer for HOURS, and nothing works. Save my life please.

edit: someone told me to check if /Users/aris/.npm-global/bin is in my path, but i have no idea how to do it. I googled it and tried a few instructions that put that directory in my path, but nothing changed.

Truffle also seems to be installed in my hard drive (as you can see at the screenshot bellow), even though when i check at the terminal if its installed, or try to call a command, i get that "command not found: truffle":

EDIT#2342 (excuse me for this btw) i checked and truffle is NOT in my path (screenshot bellow). Should i manually try and find the truffle executable file or sthing?