Airpods4 can't connect via mutiple devices

Same as the title. I got my airpods4(ANC), i have a mac air(M1),ipad air7, and a iphone 16pro, i first connect my airpods to my iphone, then my mac, but sometimes when i connect it to my mac, i found that my airpods can't connect to my iphone, i tried to reconnect,but it said failed, but my airpods can connect to my ipad and mac smoothly, while my iphone can't.

BUT sometimes i do can connect airpods to my iphone and it can switch smoothly. all my devices are up to date.

how can i solve it? I really appreciate your help!