Why Russian national football team was extremely weak in this Euro?

Their performance in this Euro was extremely poor, with 0 win, 1 draw, 2 lost (1 heavy lost)

I don't watch football, but Russian team has always puzzled me. Super inconsistent. Great wins followed by horrible losses.
A tie with the strongest team, and destroyed by a tiny country

They are always a disaster, nothing new. The amount of memes about it on my timeline...