Since 1962, only 13 Mets who have played in at least 100 games in a season have had an OBP of .400 or above. The first was Richie Ashburn in 1962. His .424 OBP was not topped until 36 years later when John Olerud had a .447 OBP, a number no other Met has come close to through 2024.
Mets top OBPs in a season

That might change this season. Juan Soto, one of only two active players with an OBP >= .400 over at least 100 games in six seasons — the other is Mike Trout — is now a Met. However, Soto exceeded Olerud’s .427 OBP just once when he reached .465 in 2021 with the Nationals. In his other five seasons, Soto’s highest OBP was .419, accomplished last season with the Yankees.
Active players with most seasons with OBP >= .400 & Games >= 100

Among the active Mets players besides Soto, only one had an OBP >= .400 in at least 100 games in a season, Brandon Nimmo doing it once, but that was seven years ago when his OBP was .404.
Justin Turner played for the Mets from 2010 through 2013. During those years, his highest OBP was .334. After the 2013 season, he became a free agent and signed with the Dodgers. In three of his season with them, he had an OBP over .400 three times, playing more than 100 games in each.
❓I’ve wondered why he couldn’t hit like that with the Mets.
The data in the tables is from Stathead Baseball.