Yeah the Marlins have been one of the worst teams in baseball when you look at their regular season success, though they have two World Series (1997 and 2003) since 1993 so in their 30 years of existence. However since even 2003, the team has been not relevant at all other than grabbing a Wild Card spot in 2020.
The Rays have had regular season success most years since 2008 so 10 years after they were established. However, haven't won a World Series.
As a fan, would be a lot more fun watching the Rays instead of the Marlins given their consistent success mostly every season. Whereas tough being a Marlins fans for 2-3 decades, but hey they won two World Series.