The other party has a problem too, just a very different kind that is ultimately synergizing well with the badness of the Republican party - utter incompetence at a lot of points.
The 2016 election was a great example of that. Dem-affiliated media giving Trump all the screen time in the world and free promotion they could, because the profits are too nice to ignore and “haha who would vote for him anyway, amirite”? Check. Running a heavily disliked candidate that previously failed (in 2008), with a heavy twinge of “it is her turn”? Check. That candidate almost entirely ignoring important battleground states during the campaign, all while Trump was campaigning very aggressively in those states (and then subsequently winning them)? Check. I absolutely hate the fact that I called it out (as soon as the primaries started) that Trump was very likely to win. Which got me clowned at the time.
This is just the most surface level easiest points to make, and only about the 2016 election. If one wanted to, they could dive into this much deeper.
I will say this though, Dems seem to have gotten their shit together a bit more recently, so that’s a nice development. However, let’s not pretend that just because the Republican party is tearing things up using their methods, Dems aren’t doing the same as well (just in very different ways that help the Reps do their job more efficiently).