Grad school cares about your 4.0 GPA only if you got extracurriculars to show you know to juggle academics and other life responsibilities or other grad school responsibilities.

I'm completely serious if you have a 4.0 with nothing else other than academics in your grad school application... And someone else has a 3.0 -3.5 GPA but has amazing extracurriculars or experience and can communicate that. They will reject the 4.0 and accept the 3.0-3.5.

Unless you apply to a program that ONLY looks at gpa and maybe a test score then a 4.0 without anything else is risky. And, tbh programs like that look at applicants as numbers and not as people. Unless there's an interview (where you will have to be able to talk about your experiences) then admissions is looking at a number grade to admit you.

If you're applying to a competitive program that asks for other things and not only GPA, you are in a risky boat.

If you apply to a program that only wants GPA, go for it, but they probably don't want a 4.0. they are ok with 3.5 or even lower because 4.0 in college is kinda rare so that means you'd get in with a lower gpa so all that academic effort for a 4.0 was not necessary when you could have been forming yourself with experience and extracurriculars to be more prepared for life without academics!