It wouldn't surprise me to see Tories do well (labour fatigue, Tory MP's in North Wales from last Westminster elections but actually vote increase larger in the south) but, imo, I can't see what they have done to deserve it.
Regarding M4 relief road, if it does get made you almost instantly have to thing about a second relief road and that's only going to cause greater damage to the environment. Meanwhile, floods in Wales get worse.
Regarding Covid, ignoring the fire-breal idea, delay of lockdown in England, schools going back for one day all contributed to more sustained level of grief under a Tory government this winter.
In the big event of the year (covid) and big event of the next 10-15 years (climate change) Tories haven't stood up well. All while making cuts to any project in Wales at Westminster level or ignoring Wales completely.