As I do not own a pironman5, rpi5 nor usb-serial, I cannot help any more than I’ve referenced in the previously posted links. I just happen to recall this issue being discussed on another forum that I follow
I’d suggest reposting your question in one of those mentioned forums. Either rpi5 (where a bookworm level solution was proposed) or adafruit, (where an adafruit solution was created)
Although not really a Sunfounder, nor pironman5 issue, Sunfounder may also be able to assist. They are really helpful!
Of course, if Sunfounder send me a free one, then I can help out more 