I don't think the Democrats' problem is that they're not far enough to the left

That depends on how you define "left." You can't balance extremism on the "right" by hewing to the middle. The deeper problem is that they're still thinking in the one-dimensional left/right spectrum.

Even on that one-dimensional spectrum, Kamala and Walz both have records of pushing radical (and often unpopular) leftist policies

Says you. They aren't that radical.

Kamala said in 2019 that she would be in favor of mandatory* gun buybacks, taxpayer funded sex-changes for inmates, and regulating social media platforms.
Tim Walz claimed the 1st amendment doesn't protect 'hate speech', put tampons in boys' bathrooms, established a snitch hotline and shut down small businesses during covid, and let Minneapolis burn during the riots
Seem pretty radical to me

First, I don't know how accurate all of that is. For instance, Minneapolis didn't burn, only a small part. And while that's bad enough, we shouldn't overstate it and make it sound like a whole city of hundreds of thousands was razed to the ground.

Second, I'm for regulation of social media and the censorship of hate speech and disinformation. But also the elimination of the office of president and political parties, democratically movable borders, absolute technocratic control of heath and environmental regulations by scientists, and new currency being given to workers instead of banks. So what you mentioned doesn't seem radical to me at all.

In other words, you don't think they're far left because you're even farther left than they are lol

What's left and what's right depends on where you're standing and what direction you're facing. I'm sorry if your identity is dependent on a simple definition of those words.