The rumor going around town is that attaching an external CC1101 to the 3v gpio pin can cause the SD card to become corrupted and possibly cause other issues. I’m seeing recommendations to use an LDO to convert 5v down to 3,3v from the 5v pin. Is that something I should consider or be concerned about?
I have also saw rumors that the Flipper won’t detect a CC1101 connected to the 3v pin. I can say that seems to be incorrect now if that was previously and issue.
I did have some tx gate issues in the past on some badly soldered boards i was playing around with , but it was mostly because bad physical connections, the FZ battery seems more then well enough equipped to run the needed power on 3-3.3v , but i did see some less solid connections cause issues like this in the past where coming from 5v does seem to be less picky on transistors swapping to open state on a lot of boards and home-brew setups with cheap components, but also some TX modules on some bands that are compatible seem to have very cheap resistors added to them that like a extra jolt of of voltage or where i removed them entirely to get TX working again and TX turned out to be more clear without resistors then with them 
But those TX modules 5 pieces for 3 bucks tend to be of quality equal to price, they work, most of the times but mostly it is just data0/gate voltage that will not flip where coming down to 3,5-3,5v from 5 instantly makes it scream loud again. So having a RTL-SDR or something alike as receiver or something listening while you are trying to use it could help notice dropping TX etc. With ESP or other external options, using the devboard options or just trying cheap breadboard cables, the only issues I really experience are usually to my personal lack of properly connecting things like they should be when i just want to try something “quick” that usually turns into 2 hours But no i did not manage to break SD storage because of abusing the 3v lanes , that story is entirely new to me. However i do agree to many SD cards and other storage devices are no longer as strong in lifespan as they used to be 20 years ago. So from dinosaur perspective i do agree that too many memory-cards get corrupted without good reason to early.
This is something I keep hearing about but never with a reference or even “this happened to me”. I’m yet to even see someone saying it even happened to a friend of a friend. I’m sure that there is a limit to what you can draw but I still have no reason to believe a single CC1101 exceeds that draw or that it will corrupt the SD card.
IIRC, 2A. More will trigger battery overload protections.
And when all the Vcc in the system does poof it is not implausible that an in-process write will wreak some havoc.
The CC1101 from what I can find maxes out at 0.034A leaving 1.966A for everything else.