I am "obsessed" by it because basing immigration rights on nationality is a defacto way of doing it by race. FOM creates a largely closed labour market that makes it much more difficult for non Europeans to move to Europe. I want an immigration system that angers both pan europeans and nationalists. Most countries have immigration systems based on individuals not nationality. Our system from 01/01/2021 will be similar to the US, Canada, Australia, New Zealand, Japan, South Korea and Singapore. Its common to have some exceptions for countries with strong ties (like the UK and Ireland will continue to have with each other) and some easements under Mobility frameworks (like Canada and US have) but not to the extent that exists under FOM, which accounted for approximately half of UK immigration.
I would strongly support a mobility framework with the EU to build on the limited provisions in the FTA but it would need to be on terms that both sides are prepared to offer to other countries. 3 year youth mobility visas would satisfy much of the demands of young people, if combined with proper funding for the Turing scheme. If a year abroad as a student, followed by a 3 year youth mobility visa isn't sufficient for a young Brit they need to make sure they are sufficiently skilled to get a visa.