So, I think the people doing that job should be making standard working class wages, and they should, for example, be elected by their respective interest group organisations to a formal legislative body that consults on and can propose legislation, but not pass it.
Like the house of Lords, but instead of being full of rich people named Baroness Killthepoor, it's an actually useful body.
Lobbyists are an informal adhoc means of essentially legalizing bribery, that has been codified over time. While legitimate good might come from that system, as you've pointed out, some kind of formal democratic system by which formalise and democratize that consultative role should be enacted.