Hi Guys,
Just a newbie here, so take this with a(ll) grain(s) of salt.
I was facing the exact same issue until I created a Table under Data (default options, including examples), on the said environment, then proceeded to create a Connection with Microsoft Dataverse.
It will take a while to create a table, it still presented the same error immediately after creating, but after 5-10 minutes all was automagically solved and I was able to copy the flow.
Btw I noticed it after doing the above and after opening the same flow under Power Apps, so there is a smaller chance that opening the same flow under Power Apps did the trick.
HTH.