You would greatly benefit from domain specific experience. The problem with university education is that you vastly over-estimate what you know. The theory is good, but practical experience trumps it. Knowing about the problems, solutions that have been implemented, what people are willing to pay and on what basis. The dynamics of negotiations, business, accounting, contract law, financing, etc are all critical.

The fast track approach would be to work for a startup in the domain that you are considering getting established within. However, sometimes working in a "legacy" firm will help you see the more deep seated problems.

Can working in my dad's small business help instead ?

Generally it is not a good idea to limit your horizons to a family business unless your goal is to perpetuate the family legacy. If your ambitions are to create something greater or in a different field, then you will need to go beyond your comfort zone.

It helps you to get insights into an industry, a feel for what they need and how customers tick. Also connections and an understanding how businesses are run.

On the other hand, Microsoft and Meta have bee quite successful with founders sans job experience.

Microsoft and Meta also had mentors and advisors, which I am not making assumptions to whether or not the OP has access to these.

Microsoft was just another small software company until the IBM opportunity came their way. Bill Gates' parents were very well connected and influential. I doubt Bill could have pulled off the deals without those advantages. Besides, IBM grossly under-estimated the opportunity. So luck has been a huge factor.

Are there any other companies where founders had no prior experience ?