Apple wants to replace the logic board and battery of my iphone

So I got the iPhone 12 Pro Max when it newly came out last year (2021) September. It immediately started giving me issues such as “no network” whenever I have this issue, the phone repeatedly goes on and off and I don’t have network for days or hours. I took it in, the y claimed it was the sim tray, SIM card, update etc. i had it all fixed but the issue persisted and then I started having pink overlay before it abruptly turns off. I sent it in finally to Apple again, they want to fix the logic board and the battery but leave the camera and front displays. I am quite confused why I don’t get a new phone but a repaired phone since I paid for a good working phone from the onset. I asked for a replacement under consumer law and they refused! They are not even sure if the logic board will fix the issue. Someone please advise me cause I am running crazy already.