Hi!
I realize this is probably more a Samsung issue more than a Linux issue, but I hope someone here knows this stuff.

So, back in the days, accessing the files on the phone was as simple as connecting the USB-cable and access the files through the file explorer. The last few years, however, have been an absolute pain in the arse. I've had huge problems with Android File Transfer, as it just freezes whenever the phone connects. This has happened with four different PCs and five different Samsung phones. Samsung's response is that I should use their software, Samsung Smart Switch (or Samsung Kies), but I am of course very little willing to bend over for their crap, when they're blocking off other methods that should've been working fine. I am also, of course, hesitant to use other 3rd party cloud services, such as Google, Dropbox etc to transfer files. I just want to connect my PC to my phone, and extract the files, goddammit! I have used AirDroid for a while, but they are now pretending that the local connection doesn't work, so all transfers must go via remote servers. That shitty app is getting more and more shady by the hour.

How do you do it?
I have both Windows, MacOS and Linux computers available, and I just want to copy over my files without going through remote servers. How?!

Thank you very much for your response!

Welcome to LinuxQuestions.

Your correct since Android dropped USB mass storage support in lieu of MTP connecting via USB can be a pain for both linux and Macs. Connecting the device to a Windows system should be a non event. Its been awhile since I've tried and it was on an older device but it should just work. I can't remember if I had to do anything special to see the added memory card.

Depends on what version of Windows you are running Windows Windows. Windows 7 needs the Windows Driver Foundation - User-mode Driver Framework installed and not sure what Vista updates are required. Windows 8+ should be automatic.

On the other hand at least for the most popular linux distributions MTP support should be already installed. Most file browsers have a built in MTP virtual filesystem which should automatically pick up the device when plugged in. Again the better support comes with a fairly up to date distribution. For other distributions you might need to install the libmtp packages.

MTP is the keyword here, and it should work on Linux just as well; for most devices.
Installing additional software should not be required (depending on what your OS came with of course) and is likely to make things worse.

There are unlucky combinations where the device is newer than the Operating system, or just way too old.

More information is required.

You could try kdeconnect, it's over Wi-Fi.

For me it just works with myphoneExplorer at work (win7 and 10).

I'd check the wire and the outlet.

You also have usb otg as a fallback.