Can I have the default Forerunner 745 watch face on the Forerunner 945?

No, unless someone provides a similar watch face in the IQ app store.

Thank you 

There is a watch face that is similar but it doesn't have access to the training load. https://apps.garmin.com/de-DE/apps/6eda8a23-2dc6-41f1-b3f8-45622f2d4570

Its madness isn't it - all these model specific watch faces and data fields - I wish they would standardize the garmin OS across their model lines - even if its just within the same sensor hardware platform (Fenix6, 945, 745, 245 for example)

I have to say the 945 has improved immensely since its launch with lots of features added from the fenix6 so I'm really grateful , but to have a lower model having more useful triathlete features boggles my mind....

Agree - I understand why the Fenix, etc. gets special watch faces, but why all Forerunners don't share the same faces, who knows.  What's funny though is I have a 945, but am using the factory watch face my 645 had.  It's just easier to read.  :)