a few links that may help …below… and yes this is an excellent choice of case for the rpi-4 i would recommend it to any new user .
welcome to core forum…
1: i don’t see the M-2 hdd can be accessed without taking the case open
2: i found the m-2 to be much faster than any sd-card
…i had my m-2 running long before core started to sell the argon m-2 case.
if you use a high speed ssd then i`m shore you will be way ahead of any sd-card even using usb 3
i found my wd-green much faster than my sandisk ultra thumb sticks or ultra sd-cards…
3: see 2
4: the remote control or infra red is a grey area not much is known i suggest you drop an email to the guy`s at argon.
https://www.argon40.com/argon-one-m-2-case-for-raspberry-pi-4.html
i like the full size hdmi outputs,very nice…very biasing,
to setup the fan trip temperature points you can use this via a command prompt as root user…
argonone-config
or you can edit the argononed.conf file in the /etc directory manually
also look here if your unsure about the fan setup and testing it out
