iPhone restarting every 3 minutes?

Hi have to disagree with Daniel here, as the error code on your phone is 0x40000. That code as been identified in the iPhone SMC Panic Assertion Failed wiki page as an error associated with the charging port assembly.

Sorry to say, iFixit doesn't have a guide to that repair, but there's a Spanish site that has just what you need.

Manuals / Apple iPhone 14 Pro Max / Charging Flex - Nobody Calls Me Chicken

The guide is in Spanish but if you view it with the Chrome browser, the translation feature works quite well.

The repair is fairly straight-forward, but the downside is that on your phone the charging port flex cable runs underneath both the battery and the motherboard, so both of those have to be removed to be able to take out the charging port assembly. Fortunately Apple hasn't gotten around to pairing the charging port to the motherboard, so there won't be any parts pairing issue with replacing it. Note that the port comes in different colors to match your phone, but realistically you can use any color port; the difference is strictly cosmetic.

As far as the availability of the part, you can support iFixit's repair efforts by buying the port directly from them.

iPhone 14 Pro Max Lightning Connector Assembly

Of course for those who are more cost conscious you can easily find replacement parts on the big three sites, eBay, Amazon and AliExpress, although other sites will come up as well on a general internet search.

Having run into phones exhibiting a charging port error code, my own success rate with swapping out the port has been very good, so I strongly suspect that a new charging port will stop the rebooting that's being such a big pain in the butt for you.