you need to discuss the wiring with an electrician before attempting any wall patching but i would put back the old cabinet pending a new cabinet for the whole area including the cooktop and/or just paint the cleaned block section of wall but it will always look rough without professional plasterboard or rendered finish and instructions on how to lay the flooring should be available from the manufacturer of your flooring ...you could probably gently remove a section to see if the brand details are on the back of the board and it would be much better to replace with a room width section rather than attempting to join as is but flooring suppliers should be able to give specific advice

Thanks for the advice. I am not planning to change the wiring, so it will be exposed a bit but it is ok given this is just the rumpus area. I am really thinking of doing plaster myself given it’s small area. We will see how it goes.

exposed wiring is a safety issue and needs a qualified electrician to inspect and redirect before any other work is done