Iphone 17 Pro Max signal issue

the signal drops while using data with my new phone, tried all trouble shooting with both the service provider and apple it self but not resolved, i would say its the problem of apple because i had same service provider with different iphone and it worked fine but when i bought iphone 17 problems started.

BTW i uninstalled the e sim and installed again with service provider but didnt work, now i dont know what should i do.. is there any procedure for complaint or something?