I think it is necessary to separate a personal bank account (with which to buy, for example, your house or personal cars) and accounts for each company (each company can include several businesses). The personal account is fed with a salary that you set as an employee of your companies or with an extraordinary dividend payment that you can activate manually. In both cases the corresponding taxes are paid.
Once this is done, the existence of a stock exchange makes a lot of sense: in addition to buying shares of other companies, you can sell your own shares to finance new businesses or for personal expenses. The downside is that when you make the dividend payment you will only receive the percentage corresponding to the percentage of the company you own.
If you own less than 50% of the company, it is no longer yours and you cannot manage it. On the other hand, if you buy more than 50% of another company you start to manage it.
Thank you and congratulations for the great work