Does positive revenue ensures positive profitability when the cost of goods sold is less than revenue?

NO way

It okay if your CGS is less but what about Selling General and admin expenses?

Positive revenue doesn't ensure possitive pofitability when the cost of goods sold is less than revenue. Other cost components (such as indirect costs, assets depreciation, total manpower cost, and warranty costs) must be caculated in order to verify positive profitability.