… and both countries are run by despots.

To the contrary, the USSR brought dramatic democratization to society. First-hand accounts from Statesian journalist Anna Louise Strong in her book This Soviet World describe soviet elections and factory councils in action. Statesian Pat Sloan even wrote Soviet Democracy to describe in detail the system the soviets had built for curious Statesians to read about, and today we have Professor Roland Boer’s Socialism in Power: On the History and Theory of Socialist Governance to reference.

How could they have materially been more democratic in a way that would satisfy you? Unless you’re talking about the Russian Federation, but that’s not what I was talking about in this post.

You fail to understand that the USSR ceased to exist. What remains is run by a despot, regardless of your feelings or intent.

but that’s another country with a different constitution

Yes.

However, the country that OP is discussing ceased to exist and thus its founding documents are pretty much irrelevant.

Do you believe the constitution created the collapse of the USSR? Are you arguing against full employment guarantees, equality of the sexes and ethnicities, etc? What specifically is your point on why the USSR dissolved, do you think the democratic process by which the constitution was drafted caused it to dissolve?

Regardless of how or why it failed, the constitution and the society it represented, failed to secure the continued existence of the country.

A constitution is not the only way to form a country and the two examples you gave both ended up with a despot in charge.