your mcu is not f405, it is f722, as suggested by the name on the ic as well as the board. so it cannot run ardupilot. however, it might run betaflight and you could try the speedybeef722 board for it.
The clueless seller calling a Flight Controller an F405V3 and it’s clearly an F722 which as noted is not supported by Ardupilot? Find a Betaflight or iNav forum.
it is not possible to have a firmware for this board. there is almost zero chance that the seller stripped it down so much that it fits in the limits of this processor, and even then it is not worth it. so, @LY_Ord even if you find/inquire the seller, you cant run ardupilot on this. betaflight/inav are the only options as previously mentioned by me and @dkemxr. @ok_danish should either replace the fc with a genuine supported board, preferably with h7 processor, but f405 also works. These clones are maybe fine for learning, but usually have poor quality/clone sensors and they have higher noise floors, and sometimes relabelled chips as well.