Help i already accepted a job but got a better offer

So i have 4 different job offers, two of which were the two main ones i was hoping for, i accepted the position at company A because i didnt think company B liked me, but it turns out they really did and sent me a job offer. they pay generally the same but company B had already agreed to give me a month off in the summer (something i really want for a summer camp job i got back to every year), while i have not yet asked company A and i dont know that my job would be waiting for me when i got back i also dont know if they if they can even offer this considering its a larger company than company B. Companies C and D will be getting declined as they were my backups.

How or can i even ask company A this? i already finished the onboarding process via paycor and have done one online training module, but my official start date isnt until 3/10/2026 which is four days away. what do i do? do i even have any options other than js work the job i already accepted...???

in hindsight this is my fault as i applied to so many jobs for my first "real" big girl job and didnt expect to do so well, so i guess im just suffering from success. TT ^ TT