I am not aware of any dashcam, you can say "save this to" or something similar, personally i prefer to push the event button on the camera and some times a remote BT button.
If the camera was to listen for a command all the time, then you cant play the radio or at least not very loud.
Seem like a lot of the things you want are not there in dashcams, as far as i know most cameras don't have the same streaming to or instantly share to social media you will have in some action cameras.
And you also say 4X4 i assume off roading, in that case i would prefer a camera on a gimbal, or with really good build in electronic image stabilization.
Mind you some dashcams do talk, but they dont listen, so all you will get are in voice what most cameras do with dings and beeps.
Things like the camera have started to record - event detected ASO.
you cant prompt a camera not even a smart action camera to save a time frame of footage, and surely not subsequently tell it to upload it to your social media account, to me there seem to be some fiddling with a app on a phone and the phone to act as access point to do that.
Some newer action cameras you can control with voise, but only simple things like start / stop recording - take a picture and so on. and there are no pre buffer for this, so either you have to record all the time, or start a recording before you enter a section you want to cave.
Most dashcams have buffered event saving, but some you just get seconds 20 - 50 or so, others like my street guardian cameras save in accordance to loop segment size, and as i use 3 minute segments this mean i get 2 of those ( 6 minutes saved / locked ) when i press the event button.
And you can view those on the APP if it is a wifi model, but there are no options to upload to social media in the APP, and no editing and i assume you would need that too if you don't want to upload a whole 3 minute segment, which is around 3-400 MB in size.
Also in a SG camera and others you will first have to DL the file to the phone, and wifi in dashcams are horrible slow,,,,, its like stone-age wifi and sending the message on bongo drums might be faster.
And slow wifi you get on pretty much all dashcams.
you will have to use a proper sized memory card, and then find your moments to share at home on the PC, and if you are one of the " i don't have a PC cuz i use my phone for everything" then i am sorry but then you have more "problems" than you need to have.
You can turn off looping on some dashcams, but that's not really how they should be used, and the smaller segments made up of X minutes, are easy to mix into one large file on the computer using just about any editing software.
If i had say 10 of the 3 minute files i use on my dashcams was on my PC and i had to make them into one 30 minute long video, it would take me around 3 minutes to boot my editing software, import the files, and start exporting them as one big file. ( export take a little while depending on the kind of footage and how you want it saved ( encoding )
but you can have a cold one while the computer finish that, or browse the internet or something.
If i had to import the 10 files first from the memory card in my SD card reader it would maybe add 3 minutes more, doing the same with the camera wifi to the phone would add something like 20 minutes due to the slow wifi.
Also the "smart" dashcams, well to be honest it are often those that are plagued with the most issues, a simple dashcam that just record when you drive, well if its a good brand / model it is much safer.