It really is just a collection of several dozen research grade implementations for algorithms + a small handful of load bearing algorithms for the entire internet. Surprisingly, OpenSSL isn't the only critical piece of internet architecture like this.
Is it still a critical piece? I thought most everyone migrated to libressl or boringssl after the heartbleed fiasco and serious people took a look at OpenSSL and started to understand the horror show that is the codebase and also development practices that clearly have not gotten better, if not gotten even worse.
The longer I develop software, the more I realize just how awful most software engineering it.