https://www.youtube.com/watch?v=CR0nAcfJ2No
@PILOU- Here is a video of what I did.

@ parel : cool pedagogic video !

Very mysterious : today that works as excepted! So more easy !

And better (very curious again): select faces "trimed" Inset don't works

but if you call Details & select "4 faces" then call Inset that works fine!

So a groove is made with only one click after the trim with the Inset "0"! (curves killed)
No need to select one by one as the image!

PS Works only for ortogonal path ! Better than nothing! :)

About the Chipp 's video above...
You can make the same more easily with enable the Grooved option! ;)

You can also replace the Inset "0" by a value and at the end make a boolean Union!



Inset Multiple :)

OK-Solved what I originally came for. Posting a video of a decently repeatable workflow.
https://www.youtube.com/watch?v=pLiOV2rPcYo

Thanks for this video

-Zooen

Excellent!
by parel

Thanks PILOU!