Saitama wasn’t powerful enough to one shot Garou at every point

Yes, I meant that Saitama was growing powerful enough to one shot garou soon enough and here "soon enough" may even be milli seconds considering how fast both chars are

Also I don’t really think you should apply math to the graph, all it really does is show that Saitama was growing much faster than Garou and was always above him

True but I am just saying that "much faster growth" was fast enough to make Saitama tow times stronger in a span of two punches only.

And idk where you pulled that 7.5 number

I linked the source.

the seconds/minutes since we have no idea how long the fight lasted.

I told "if" fight lasts a minute which means it is a hypothetical situation.

At their speed the fight could have lasted like a second considering PS vs Garou lasted like 2 seconds

Yeah it's highly possible but if it's actually true then it would mean Saitama grew 60 to 80 times in just 2 secs which only makes him more OP.