That's exactly where you're wrong. These drivers usually come from the chip manufacturers, with a few adjustments, and not from the card manufacturers.
If you work with truly professional products, e.g., Supermicro, HP Business, RME, etc., you'll notice the difference clearly, especially when problems arise.
Support, development, and long-term testing (for bug fixes and reliability) are three major cost centers for such devices/products.
It's precisely in these areas that they cut corners.
I consider Topping to be significantly more innovative than SMSL, Sabaj, and Loxjie in terms of development, but the rest unfortunately falls completely short.
When it comes to firmware, they try harder than their competitors, but not always successfully. Furthermore, not all errors/problems can be fixed with a firmware update.
The price of the D50 III is reasonable, and that of the DX5 II is extremely reasonable. You may have to live with a few limitations.