Restoring an iPhone 11 Pro Max to a new iPhone 16 Pro Max

I mistakenly put my iPhone 11 through a washing machine and now it doesn't work at all. So, I bought a 16 Pro Max with 1TB of memory.

I am not able to transfer my iPhone 11 backup to my new iPhone 16. The backup is on an external hard drive not iCloud. I'm using a 2013 Macbook Pro w/ 16GB of memory that was running Mojave. I have used iTunes to back up my 11 for several years.

After about 2 hours of doing a restore to the 16, I got this message, "iTunes could not restore the iPhone "My iPhone" because the backup was corrupt."

I am hoping it's not corrupt but just some incompatibilities. Apple Tech Support suggested I upgrade to Catalina. I did that and could now see the phone in the Finder. When I clicked on it and then clicked "restore," I did not get an error message this time, but after an hour or so, the restore window went away and my phone came out of restore mode but did not have any of my apps, photos, etc. from the restore files.

Apple has washed their hands of this since they don't deal with older systems.

Any suggestions? My thinking is to return the 16 and buy a "new" 11 from a third party and see if the restore will work. I was fine with my 11 so I would be ok using a new one. I'm hesitant to buy one initially because I don't know if I can trust the sellers. Some I've seen one line say, "shipped from China" so I'm worried about compatibility.

In the meantime, I have no access to any of my apps but I can use the phone for calls.

Thoughts?