No, Commission now has rather a lot of own revenue tax-raising powers. From all customs duties on imports from outside the bloc, to revenue from selling carbon credits, a levy on plastics, and some of the VAT income (0.3%). By formal tax-raising power, the Commission is the fifth-largest country in the EU.
But the bigger problem is that people look at the income side only, and assuming spending must match. It doesn’t. The EU have run up multi-trillion debts in several non-obvious mechanisms, none of which have any prospect or expectation to be covered within national subscriptions. There’s lot of debate about QE and COVID solidarity bonds, but the main debts and subsidies are dozens of times larger and pre-date COVID. They are hidden as “loans” which have really been grants, where the issuing institution has a “net zero” financial position including a theoretical but not practical claim on the underlying asset.
To take a random example, Commission currently owns 60% of the local tax income of Communidad de Madrid, until 2052, which is paying down loan on money the Commission already gave and has been spent. How is Madrid is supposed to live on 40% of its normal tax base for a generation? Oh well that’s easy. All they have to do is get out another loan to pay their current operating expenses, pledging another 20% of their tax income to secure it. That’s how they got into this position - three tranches of 20% so far. Perhaps you can see the problem, although Madrid can’t. So you can see why I’m sceptical of saying EU Commission doesn’t have tax-raising powers.