So if I leave one job off my tax return and keep the other three will that effect my return?

No----ALL of your 2021 income has to be included on your 2021 tax return.   You cannot pick and choose which income to report to the IRS on your tax form.  All of it has been reported to the IRS by your employers so the IRS expects your tax return to match that.

You started off with your first W-2 and your refund look high?  Then you added another W-2 and it stopped looking so good? That is normal.  When you added more income, your tax liability increased, so you saw your refund decrease.  The program began by giving you your standard deduction—- which lowered your taxable income. So you are not being taxed on as much of the income on that first W-2.  Then you added taxable income--so the refund went down. Your refund (or tax due) is based on the total of your income, not “per W-2.”  Wait until you have entered ALL of your income and deduction information.  You can't really tell anything until it is all entered.  That “refund monitor” does not mean anything until everything has been entered.

https://ttlc.intuit.com/questions/2273878-why-did-my-refund-drop-when-i-entered-another-w-2