There is no such thing as "OpenWRT", it is "OpenWrt". OpenWrt is a registered trade mark.
If it was WRT, I would expect it to be spelled out as in an acronym that does not make an easy to say pseudo word, as for example in PDF (Portable Document Format). Contrast with NATO (commonly pronounced as "Nay Toe" in English.)
As we established earlier in this thread, OpenWrt is derived from its origins as an alternative Linux based operating system for the Linksys wrt54g, which was sold as a "wireless router".
All of what I just said is perhaps being a little pedantic, but as there is no official way of saying it, we can, in truth, all use whatever we like.
As almost 100% of work on the subject is done by people who in turn communicate almost exclusively by some sort of Internet messaging, most of us, until the availability of video calls became commonplace, were blissfully unaware that others may well be pronouncing it differently.
If you were to send me a message saying "I think we should create a custom OpenWrt image for this project", I would know without thinking exactly what you meant.
But if you announced in a video call "I think we should create a custom Open Wee-Er-Tee image for this project", I would wonder what you meant (or at least I would have until now!).
This of course works both ways - herein lies the problem 