HSA early withdraw

Hello, this year my company started a new HSA plan and gave employees a $1500 free start up.  I haven’t touched said HSA this year but was curious wha true penalty would be for early withdraw.  I read up and saw a 20% deduction plus it will be taxed.  With open enrollment I’d personally like to go back to the traditional co pay plan meaning I have this free $1400 sitting here which honestly can really be helpful for tackling student loan debt.  If I were to take this early withdraw what kind of money would I realistically be seeing back? The 20% reduction makes sense but I’m not entirely sure how much loss or gain or whatnot would be removed from my taxes. Are you able to spread some light?  Thank you in advance!