I've always said ploh-ver (rhymes with clover), but that comes not from any birding experience, but from drinking Andytown's Snowy Plovers[1]. I believe the staff there has always said ploh-ver as well, but it's been a while and I could be mistaken.

Seems like jury is out amongst birders[2]

[1] https://thebolditalic.com/the-snowy-plover-is-the-tastiest-d...

[2] https://www.10000birds.com/ploverpronunciationpoll.htm