They will rely on different chips
AMD can prepare not only the budget A620 chipset, but also its even more affordable version.
Resource HKEPC claims that the A620 will be available in two versions. The Promontory 21 version will appear first, and later another version will come out, possibly on Promontory 22. Since Promontory 21 itself is used in more expensive motherboards, it is not well suited for budget models. And the cheaper Promontory 22 will allow manufacturers to produce more affordable boards.
Technically, there should be no difference from the user’s point of view. AMD has previously promised motherboards for the AM5 platform starting at $125, but so far the minimum prices for models based on the B650 chipset start at about $160.