I am not associated with the Lazarus project at all but I did develop in Delphi over 22 years ago and I still do some development using Lazarus. I hope to do some tutorial videos on this to help those new to the environment.
Were you a 68k-era Mac dev, by chance? That's my biggest mental association with "Object Pascal". I was only old enough to be a beginner-level user in those days and never got to ('had to'?) program anything on them, but it always seemed like it would be fun to revisit and see that Other Side of my childhood System 7 :)
No, I started with Turbo Pascal in the late 80s and early 90s and then moved onto Delphi, Turbo C etc later. I programmed in Delphi till about version 7/8 when Borland decided to implode by going after "Application Lifecycle Management" etc.
So it is best to see Free Pascal & Lazarus as the free and open source alternative to Object Pascal & Delphi respectively.
Of course, now the term Object Pascal is not used at all. Delphi is used to refer to both the language and the IDE now.
About Free Pascal, it is largely compatible with Delphi/Object Pascal but there are minor differences. https://wiki.freepascal.org/Lazarus_For_Delphi_Users
Here is a write up on the advantages of Free Pascal: https://www.freepascal.org/advantage.var