Hello!
I am not an accountant, but as far as I understand, Equity is exactly the the right account for this.
Whenever I myself have a question like this it helps me think and google assuming that I am running an accounting for a small business.
In this case Equity is everything which owners invest in the company or draw from it.
What you are doing when initiating
"Opening Balance" is equivalent to closing old company and transferring all assets as well as liabilities to a new company, and this has to go through Equity as far as I understand.
It is definitely not Income and Expenses