Migration taking 48 hours

I'm using migration assistant to transfer from my old High Sierra iMac to my new Monterey iMac. The computers are connected with an Apple Thunderbolt 3 cable and an Apple Thunderbolt 3 to Thunderbolt 1 adapter. The computer says that the data is transferring via Thunderbolt at a rate of 600KB/s to1 MB/s. Started it last night, 30 hours to go. There will be a total of 48 hours to transfer about 800GB.

Is something wrong?