I don't think Russians actually thought that. Its just that if they publicly pointed out the issues with Telegram and publicly suggested better alternatives, bad things would happen to them.
It doesn't matter what the license chatgpt spat out says. If they forked from a Foss base repo, then all of the code they make will be FOSS too. This is great.
I use Wire. Its the best option right now. Better than SimpleX, Signal, and Matrix for many reasons