This comment from issue #17064 suggests refactoring OSSL_LIB_CTX to avoid locking issues:

I actually think we should consider refactoring the OSSL_LIB_CTX code. It's based around CRYPTO_EX_DATA which makes conceptual sense - bit it makes the locking considerably harder than it needs to be. Take a look at the locking in ossl_lib_ctx_get_data and then back slowly away. If we could get away without having to take the ctx->lock all the time (which I think might be possible) that might be a big win.

Part of the problem described in #17064 is due to lock contention in ossl_lib_ctx_get_data