Phone reboots every 3 minutes

Purchased 14 Pro Max Dec 2022, last Sun Aug 13 I plugged it in to charge, came back to black screen and nothing worked to revive it. Went to Apple store, they sent it for repair, determined couldn't be repaired so they replaced it. 2 days in with the new replacement and, out of nowhere, it started rebooting every 3 minutes. Tried restore, trying various basic scenarios (it's already updated to current software, trying with & without WiFi, data etc.) and nothing changes.

Seems, from reading around online, 14 Pro Max is really buggy, Apple's Edsel. Going back to Apple Store Monday, but this is starting to irk me. Many have had this problem while recharging, but for me it doesn't matter.

Thoughts anyone? Thanks!