Retirement tax questions

STOP using the term "W2 Contractor" as there is no such thing just like there is no such thing as a "tiger elephant".

 

If you get a W-2 then you are an employee and cannot open a SEP IRA at all.   

 

However if you are a contractor that gets a 1099-NEC and you report your income on a Sch C then a SEP IRA is possible.