Nearly a year ago you were claiming that:
The question in the OP seems to water down that assertion. Software creation requires many prior steps, being one of the primal ones to create an exhaustive functional and technical requirement description, and then exploring the platform that best matches those requirements (or go for a custom build approach is nothing else seems fit).

Many projects fail for not performing these steps with the necessary dedication, only to find out later down the road that the chosen platform does not meet the functional or flexibility needs.

In any case, an Exchange is no small matter. Taking custody of other peoples crypto assets, and being a center piece to their trades needs a professional team behind, with clear knowledge and know-how of what they are doing. The doubts expressed in the OP would lead to doubts of all sort on the exchange being built itself.