It really depends on how much your revenue, type of business and how much tax consultant fees you willing to pay. If you asking big 4, just prepare the some 5 digit tax fees.

I guess you can just find a normal small and medium size audit/accounting firm will do. If just normal sole proprietor company, then everything are much easy and cheaper for the service fees.

You not even register for a company? Then why bother submit tax?

Only if you plan to get a loan and asset, then first thing first register a company, and prepare complete book keeping/accounts.

Then you talk about tax submission, Big 4 100% will refer you to smaller size Tax/Accounting Firm. I could said their customer target are Listed/MNC, they don't even look at small peanut company although profitable.