Investigate and discuss the legal implications and practicalities for the UK becoming an EU member state again or to reach a status like EEA standards or a close relation like in the Benelux agreement

An investigation of the legal implications and practicalities for the UK becoming an EU member state again or to reach a status like EEA standards or a close relation like in the Benelux agreement.
The UK and the EU member states face significant issues as no refined trade agreements had been set up before the UK left the European Union. In fact, it is now important to know if trade agreements with important EU member state trade partners can be done despite the legal implications. Additionally, it should be explored which legal implications and practicalities for the UK becoming an EU member state again really are.