But your current LMIA is NOC 21221, and a mix of NOCs doesn’t count. So this stream is not tied to EE so your EE profile is not relevant. So you must have:
To meet the work experience requirement, you must have at least two years of cumulative paid full-time work experience (or the equivalent in paid part-time work) in the same occupation (same
National Occupational Classification code) as your job offer.
You must have gained this work experience within the five years prior to the date you submit your application, not the date you received the invitation to apply. If your work experience was gained in Canada, you must have been legally living and working in Canada.
So you cannot count your Canadian experience as it is for a different NOC. What is your OINP score again? If you have two years of experience in the NOC within the last 5 years and a high enough score then nomination is possible. Since you are on a LMIA exempt work permit, using your current employer for any past experience prior to being in Canada is problematic because they had to show that you were fulfilling the duties of your current NOC. They could have done the LMIA exempt permit in NOC 21231 from the beginning.