There's probably a confusion between residency as such and lawful residency specifically.
With your documents (Council Tax, HMRC, P60, ect) you prove that you were actually resident in the UK.
With your status (EUSS) you prove lawful residency - see my highlighting. Hope that makes sense.
Please refer to the section in the guidance on Lawful residency:
https://www.gov.uk/government/publicati ... bookmark14
"Lawful Residence
You should have been in the UK lawfully during the 5 years (or 3 years, if applying as the spouse or civil partner of a British citizen), before making your application.
Under The Nationality and Borders Act 2022, you will normally meet this requirement where you have been granted indefinite leave to enter or remain in the UK. This means that, in most cases, you will only need to demonstrate that you hold valid indefinite leave in the UK in order to meet the lawful residence requirement. You will not normally need to provide evidence of your immigration status during the 5- or 3-year period.
If you are an EEA national, supplying evidence of your settled status under the EU Settlement Scheme (EUSS) will also normally meet this requirement. That also means you will not need to send evidence of what you were doing in the UK prior to being granted settled status.
This includes people who did not hold comprehensive sickness insurance under the EEA regulations whilst either a student or a self-sufficient person. You can now meet the lawful residence requirement simply by showing you have been granted settled status under the EUSS. You also no longer need to explain why you did not hold comprehensive sickness insurance."
