Well, Oberon-2 (designed and published by Hanspeter Mössenböck in 1991) was indeed closer to C++ than its predecessor Oberon 87 and 90, but definitely not a true alternative to C++ (because it only supports a fraction of the C++ features). Neither is the optimization done by the available Oberon compilers comparable to what we see in C++ compilers, not even in 1997.
That's why you would use o2c, which can use gcc-13 or clang-14.
Though I'm convinced that this ship has sailed, with go replacing oberon
As a bit more comfortable alternative to Oberon I would suggest Modula-3.
https://github.com/modula3/cm3
It even comes with a GUI library, which even though developed in the 90th Stil, works on x11. I find that quite fascinating :-)