I thought I didn't get the third stimulus but I did. How will that affect my refund amount?

I did some poor internet digging and since it is a government subsidy it isn't taxable income (right?).  I am clearly no expert here, but if my return is going to be a lot less than I was expecting then I need to come up with a plan B for my financials. If someone could explain the process behind stimulus checks and how it affects my refund I would really appreciate it!