[Max]

This instrument in the video calls “Баянита 43” – Bayanita 43

https://www.google.com/search?q=%D0%91%D0%B0%D1%8F%D0%BD%D0%B8%D1%82%D0%B0+43&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjI6pW_6q7qAhWPw6YKHWDmDfkQ_AUoAnoECA0QBA&biw=1760&bih=860

Russians have special different names for Button Accordion. It calls “Bayan” (Баян). Well, technically it is also has slightly different construction (for example, reeds are placed on single plate, like in melodica!) but roughly you can consider it as Button Accordion. So very often Button Melodica they call Bayanita. But name Accordina also is used.
Here is interning review of another classic and self-made MIDI accordina (only in Russian): https://www.youtube.com/watch?v=leJO1qkNq3w

P.S. Button accordion in Russia significantly popular than keyboard one.