You need to do more reading on the concept of Sides, also please look at the lists in this thread:
Most of the issues mentioned in that thread come from people inheriting the bad habits of people who make YouTube videos about how to mod.
I don't have a Mac so this is about the best I can do for you in that regard: https://stackoverflow.com/questions/15826202/where-is-java-installed-on-mac-os-x
Now we have the original problem, you added mods that were created after the original pack was made, some of these mods require a newer Forge version than the one the pack originally shipped with.
In other words the issue isn’t “Forge is missing”, it’s “I need a different version of Forge”