HT206D: Best new 40$ AC/DC Clamp meter technical evaluation

[duraluminium]

I have recently bought a HT206D off Amazon for 33.99EUR. It claims AC/DC clamp current measurement, Low Z mode (AC/DC), capacitance, diode test (3 V), frequency, duty cycle, temperature, LPF in AC test mode, NCV. Included are probes and thermocouple. The device seems very good, measurements correspond to those measured on a Peaktech 2025, so for non precise work seems great.

I have taken a few pictures, and am curious for some input from our engineering folks as to safety, input protection and electrical integrity. The device claims 600V Cat III.

One question I have, in the manual it states that Resistance/Diode/Capacitance/Continuity and frequency/duty cycle mode are not to be used with voltages over 10V. I 'accidentally' tried the frequency/duty mode on 230V grid voltage, and it worked fine, showing 50Hz/50%. (the AC/DC voltage mode also has a frequency measurement by pressing the function button.) Do I risk damage by using resistance/././. and frequency/duty cycle mode with higher voltages? Is the "not above 10V" just a generic cop out for some kind of safety requirement? Perhaps someone can comment on all this looking at the circuit board pictures.
Do I risk damaging the meter by quickly switching through (possibly non compatible) modes with the probes still connected to grid voltage (I understand this is bad practice)?

The main chips are:

• DM1106EN XY200301 (microprocessor)
• FT24C02A 9w5CDE (EEPROM)
• 2x GS8552 TE158A (op amp)
• crystal X1 marked 4.000

Find attached some pictures I took of the board. Look forward to some analysis and commentary. I can say as a first impression, I am quite happy, certainly the bang-for-buck is very good.

Imgur link to full res images