Section 179 plus depreciation deduction?

I am an owner operator truck driver that began in March of 2020.  I purchased my truck outright via a home equity loan.  I was guided to a section 179 deduction where I could take the entire purchase price ($50,095) as a deduction, or enter my own amount.  I entered my own amount (8,000) thinking I could do smaller amounts like that for the next several years.  However on the tax form, there is a 3-year depreciation schedule stating $42,095, which is the purchase price minus the $8,000 I entered.  So my question is, will I continue to be able to take a section 179 deduction for this truck in smaller chunks over several years, or is it all or nothing this year?  
I guess I don't understand this dynamic between the section 179 deduction and depreciation schedule.  The TT suggestion was to take as big of a section 179 as I can year one, but I would prefer to spread it out.