FY3200S internal impendance problem/modification

[Pygmalion]

I have noticed that at high output currents (large voltage amplitude + small resistance load) the internal impedance increases drastically. For example, for an amplitude of 10V (20Vpp) and a 10Ω load, the internal impedance is about 100Ω (the voltage amplitude on the resistor is only about 1V (2Vpp)). Is there any modification that can improve the performance of the FY3200S in this regard?

See also: https://www.eevblog.com/forum/testgear/measuring-the-esr-of-capacitor-with-feeltech-fy3200s/