It's worth looking here : https://github.com/dkobak/excess-mortality for clear statistics. There is a big difference between what is reported and what the actual numbers work out to be.
I believe it's (now) listing UK up to 2020 Week 51, and Bulgaria to 2021 Week 3.
That's a 5 week difference in which Bulgaria was hit pretty hard. We don't see the effect in this data set of the British variant yet.