I am using unstable branch - and pacman 5.2.2-5 has been here for some time (2021-04-21) working totally as expected.
Also I am old school - that is, I use terminal for almost everything.
If you are having issues it is necessary to see the process as a three part process.
- All packages are downloaded
- All packages are verified
- Unpacking and installing
It is not clear which step you are referring to.
The first step is depending on your internet connection and the mirror(s) in your mirrorlist.
Second stop is usually a no-brainer but can involve signature issues which must be resolved before the update can be executed.
Third step is involving your system and this process is influenced heavily by your system, e.g.
- your configuration,
- the number of kernels installed,
- the state of your root partition’s filesystem,
- the state of the disk device holding your root partition,
- the type of device holding your root partition (USB devices age faster than internal devices),
- the type of updates e.g. updating the window manager and related graphics can benefit from being run from a TTY
- and probably some I haven’t thought of.
So if your issue is with the third step - you can e.g. remove unneeded kernels before update, you can fsck from a bootable USB.
When you are done checking the filesystem, you can -using the same live system - chroot your system and run the update inside the chroot - this will ensure no open files or in-use libraries while updating.