First, try.
Then as last resort,
Mythic+ Legion Timewalking
In addition to the normal Legion Timewalking, players are able to run the available dungeons on the Mythic Keystone difficulty. When Legion Timewalking is active, players can talk to Ta’hsup by the Great Vault in Oribos to obtain a Timeworn Keystone, allowing to run Legion Timewalking dungeons in the Mythic+ difficulties.
Unlike other Timewalking dungeons (where you’re scaled down to the dungeon’s intended level), these dungeons instead scale up to the correspondent Shadowlands Mythic+ level. The Timeworn Keystone received is one level below your current Shadowlands Mythic+ Keystone.
All dungeons available during Legion Timewalking are also available in the Mythic+ difficulty.