If you have 5 years of experience as a Senior Back-end engineer you can get something between 2000€-4000€ net (after taxes) in the Bulgarian currency lev - BGN. The Lev is pegged to the Euro at 1.95BGN for 1€. In the capital where the tech jobs are located with that kind of salary you can afford anything you want.
And what salary would you get for Google in London?
FYI as an experienced professional I have just been pitched a couple of civil service jobs in London grade 8 to Grade 7 at around 75k - and that would give me about 6.5 k
That's the eqvielent of a full Colonel / GS15 if its the higher grade.
And I bet a FANG in London pays way more than that as do train drivers
FYI, and I kid you not, FANG in London pays 1/3-1/4 of the same job in Seattle (not even going to go into SV numbers). UK taxes are of course double, and rents similar, if not more expensive for London.