Mathematics GRE

I am wondering whether I should resit the exam in April (or October) of next year.

I have a score of 850 (84th percentile). I will be working full time (roughly 50 hours per week) from mid January, so from then onwards I will only be able to do roughly 8 hours per week of study (if I try to). What tier of university could I expect to get into (T10/T20) with my current score (would be open to a statistics phd if needed too)? Would it be worth resitting despite the stress of studying and working combined?

And in terms of study, would doing Steward (calculus), Artin (algebra), + IMO prep (for the more geometry style questions) be good prep (I've already done princeton GRE and all the existing practices including mathsub and rambotutoring).

My profile is:

Undergrad Institution: T5 Aus
Major(s): Math
Minor(s): Data analytics
GPA:4
Math GPA:4
Type of Student: International male

GRE Revised General Test:
Q: xxx (xx%)
V: xxx (xx%)
W: x.x (xx%)
GRE Subject Test in Mathematics:
M: 850
TOEFL Score: (xx = Rxx/Lxx/Sxx/Wxx) (if applicable)

Program Applying: Pure math (but considering statistics)

Research Experience: Honours (PDEs)
Awards/Honors/Recognitions: deans list every year, prize for top thesis in my cohort
Pertinent Activities or Jobs: None
Math Courses Taken: group theory, ring theory, topology, functional analysis, stochastic analysis, complex analysis, PDE theory, differential geometry, galois theory, semigroup theory, probability theory, measure theory
Any Miscellaneous Points that Might Help: 3 recommenders all like me and have some connections (one is well known).
Any Other Info That Shows Up On Your App and Might Matter:

Your score is good enough. The general consensus is 80% for the top places, anything past that won’t make too much of a difference. Focus on other aspects of your application.

Of course, you can retake it if you want, but your score will not omit you from certain places, even the best. It’s good enough to get past the initial filtration.

If the rest of your application is weaker, a higher score would help.

Does anyone know about the average GRE math subject test score at top schools (i.e. Harvard, MIT, Stanford) for pure math? Is it worth sending an 85 percentile score to these top schools? I won't be able to resit the exam.