Countries aren’t just economies. Scotland was colonized by England and it’s reasonable for them to want to be independent. It’s also reasonable for them to want to remain in the UK. Trying to paint one side as the one Russia supports is an ugly way of treating a decolonization movement.
Aren't you a German? (Maybe I am mistaking you for someone else.) If so, I would like to remind you of the German saying „Nicht alles, was hinkt, ist ein Vergleich“.
Your analogy is very, very stretched. One can definitely say that suppression of Highlanders after the defeat of the last Jacobite Uprising was somewhat similar to other British military actions, including those in India, but that was the standard of the day in the 18th century.
Scotland was in no meaningful way "colonized". The local elite kept their power, their property, and got adequate representation in the common British Parliament, which meant real influence over the legislative process and formation of governments.
Can you name any Indian MPs sitting in the Westminster back then and co-determining the next budget and the next Prime Minister? No.
After all it certainly doesn't make economic sense.