Opinions on the Welsh name 'Celyn' for a boy?

Hi everyone! My partner is Welsh and we are considering the name Celyn (pronounced KEL-in) for our son.

We love the name, but we’re curious about how it lands with people outside of Wales. Here’s the context:

It translates to "Holly."- the plant

In Wales Holly/Celyn is heavily associated with Christmas and the Winter Solstice.

We live in the Southern Hemisphere, and he is actually due right around the Winter Solstice here (June). It feels like a nice way to honor his heritage and the season he’s born into.

Our main concerns are whether it sounds too "feminine" to those unfamiliar with Welsh names, or if the pronunciation will be a constant uphill battle with Kiwis and Aussies pronouncing it as “sell-in”

What are your first impressions? Will he be a Sell-in his whole life and Does it work for a boy?