The initial problem with both Voyager and Enterprise was the captains (or the actors hired to play them).
Archer - as portrayed by Scott Bakula - was too wishywashy, especially in the first seasons. He has a backbone one minute, then he doesn’t. He’s decisive, then he isn’t. The inconsistency in how he commanded the crew, in how he made decisions, was annoying, and made his character weak. He always seemed to be the wrong person at the wrong time.
Janeway - well, according to Kate Mulgrew’s portrayal - if a woman wants to command a starship, she has to speak like a man. Every time she would switch from a conversational voice to that attempt at a deep-throated captain’s voice, I winced. So unnatural, so unconvincing.
Each had good episodes.
Enterprise even had a few good ones in season one (the first P’Jem story, which helped paint the Vulcans as meddling puppet masters comes to mind.). One thing Enterprise gave us was a better understanding of the Andorrians (and Empress Sato).
Voyager was an anomaly of Star Trek in that some of it’s most promising episodes and ideas were in the first season (then abandoned or muted for whatever reason). The “One ship, two crews” theme should have been a goldmine of stories, but was quickly smothered. Neelix’s “they have such a beautiful ship. Why do they keep risking it?” [paraphrase] was spot on, and marked the point where the series abandoned originality and really became regular Trek. Voyager should have continually deteriorated so that even lessor threats would have real consequences, but it didn’t (how many shuttles did it have?). I don’t know what to make of Seven of Nine - a late addition designed to drive ratings. Her story arc took too much time in the show and in the end belittled the Borg (and by association, Picard and Sisko).
They were all flawed, even TOS, and the new one will be too. But hopefully it will be Trek at its heart and not JJ-Trek.