That seems unlikely. The play store lists it at 10m+ downloads and it's still a very Chinese app. I checked it out myself. This is people trying to troll the US government
what seems unlikely? it's simply a fact that many are going to the other app. as you said yourself, 10m+ downloads on play store, #1 on ios app store, etc.
RedNote don't have english user interface, and it have worse censorship compare to tiktok or facebook.
Unless you want to learn Chinese and/or spend time to navigate around the content modulation system (not very hard, it just different), the experience ain't great.
I think they do have an English user interface since yesterday, which may still be unpolished. TikTok is available in many countries under their own languages though.
Rednote is a popular meme at the moment for obvious reasons. But TikTok has around 170 Million users in the USA. What you see at the moment is a loud minority checking out the app and creating content. This is something happening all the time with Social Media and especially TikTok, loud minorities doing something, and people hard overrating the numbers. There is simply no way that with Rednotes state at the moment, we will see a significant number of users switching from TikTok to it. Maybe at the end we will see some millions switching.
That depends on the definition of "many". Some use it relative, some absolute. On its own, Millions can be a big number for a service, but in relation to the absolute amount of TikTok-Users in the USA and Globally, it's just a few, a handful, more than 3, less than a majority.
They are simply different translations, period. The book you mentioned is usually referred to as "红宝书" (Red Precious Book). Don't know where the translation on Wikipedia comes from.