Good job !
I highly recommend trying out the various online regex editor.
These WISIWIG kind of editors are great because you immediately see what the regex is catching and for what reason.
I took the first one in my search results but try different ones.
Also I used GPT to get some regex for some specific strings and it can be helpful to get a quickstart at building a specific regex.
In that case I was building a regex for a specific log from postfix.
PS: just make sure to select the correct flavor of regex you are using in these online tools.
Edit: Also one of my favorite YT channels has pretty cool videos on RegEx : https://youtu.be/6gddK-cOxYc
Meh, sauces are not real. Do your own research folks.
Take that Big Sauce.