the full report is here:

https://www.internations.org/expat-insider/

the UK scores below median on Quality of Life (Travel & Transit, Environment & Climate, Leisure Options, Health & Well-Being, Safety & Security) and Ease of Settling In (Local Friendliness, Finding Friends, Culture & Welcome), as well as Salary & Job Security and Work & Leisure.

it's especially low on Personal Finance (50) and Housing (42)

compare that to germany:

high on Quality of Life and Working Abroad (Career Prospects, Salary & Job Security, Work & Leisure, Work Culture & Satisfaction), median on Personal Finance, but extremely low on Ease of Settling In and on Expat Essentials (Digital Life, Admin Topics, Housing, Language)

the low score on ease of settling in is pretty much why i left germany.