data transfer keeps failing

Synopsis: We (both the Apple Store and I) are unable to get a data transfer to finish. I think it may be because the source (old) machine is running Monterey and the target (new) machine is running Ventura. Might this be the cause??

No need to read further if you think it's as simple as that.

Detail:

My wife just bought a new MacBook Pro. I assume this new laptop is running Ventura.

She took her current MacBook Pro, which is running Monterey, in with her when she went to pick up the new one and requested that the Apple Store transfer the data from old to new.

The folks at the Apple Store called a couple of days later and said they were not able to transfer the data. The reason they gave over the phone is that they tried twice and it 'failed' both times.

On the 1st try they got an error message which indicated that the transfer had 'failed' - with no further detail.

On the 2nd try, while the transfer was happening, the process 'stopped.' There was no error message, but it basically transferred a couple of MB and then made no progress for several hours.

We have a backup of the old machine on Time Capsule at home, but of course that is Monterey based.

If the answer is yes, then I guess what I will need to do is upgrade her old laptop to Ventura and then back it up to Time Capsule, and then use an ethernet cable to restore that backup to the new computer.

Thanks for your help!