To achieve chip load recommendations to suit materials and cutter sizes I’ve been steadily increasing my feed speeds.
An X Carve, and most hobby machines do not have the power to achieve recommended chip loads for most tools.
As for your rounding issue. Make sure both CV Distance and CV Feedrate are both off.
In General Config, make sure "Stop CV on angles" is checked, and set to 89. All other CV options should be off.
If it still rounds your g-code, then can you post the code?
And try setting the angle to 60, or 120, and see if it makes a difference?