If you like VOY and DS9 and would like to see the series continued, you're in luck. There are nineteen DS9 novels that contonue the story for like another year and they're pretty much all great (In this list they're the dark blue ones, starting at Avatar, until The Soul Key). If you like Cardassians, check out A Stitch in Time, which is basically a Gark biography in the form of a letter to Bashir, written by Garak actor Andrew J. Robinson himself. Beyond that Una McCormack's DS9 novels tend to feature Cardassians and do a great job with them.
For Voyager, there are basically two relaunches, four books by Christie Golden continuing off from the finale and spanning a few months, that I don't think are particularly good, and a bunch of novels by Kirsten Beyer (who also works on Discovery and Picard) that I consider some of the best TrekLit, but they kinda spin out of the Destiny trilogy, that Thrawn mentioned, so it's probably better to read that first.
Other than that, there's the Vanguard series, which is set in the 23rd century, and is kind of a spy story meets political thriller meets starbase on the edge of Federation space meets ancient mystery type story, with Tholians, Klingons and civilians thrown into the mix. It's a bit more dark than the relaunch stories, but rather good.