Force cautionary time signature

I find lots of posts about how to hide unwanted cautionary time signatures, but not how to enforce them.

My Situation:

I am writing a lead sheet in 4/4 but the last two bars are in 3/4. So when the form is repeated, after the second 3/4 bar the song starts over in 4/4. Therefore I’d like to have a cautionary 4/4 just before the repeat barline. I cannot find a way to do that except for creating it with a font as a workaround.

Additionally, the song has a two bar coda, which is notated directly next to the bars in question. The coda will come after the last playthrough and also is in 4/4, so there actually is a new time signature after the 3/4 bar, which - in this special case - should make it even easier to display the 4/4 warning. But so far I have not been able to do so.

Dorico won’t show a cautionary time signature at the boundary between the end of the preceding repeated section and the coda, I’m afraid: you will need to create your time signature as text, as you’ve been doing.