The Russian-speaking person is much more familiar and understandable precisely the form of the word with the prefix "от", which is actually a little less literate. The wording "отсканировать" in QR context is used, for example, by Google: https://support.google.com/accounts/answer/9283368?hl=ru&co=GENIE.Platform%3DAndroid

The extra mention that you need to scan a QR code (not just "этот код") does not add more characters, but increases the clarity of the text.

In general, I'd rather change the wording altogether to the one used in the MacOS version

The mobile app currently uses "Подключить устройство" in place of "Scan QR". It can hardly be replaced with something short enough to fit in #2, so it can be shortened to "Подключить" (should be easy enough to guess) and moved here. It's a bit too long anyway, but not much longer than #2 in English (35 characters), so it should fit just fine.