I also couldn't get the raspistill product installed. I don't think it will ever be supported as there seems to be a range of libraries for the 64 bit version and probably has been abandoned after "Buster". Tom's hardware goes into it in more details:
However, just in case that get's lost or deleted, some interesting commands are:
Gives a preview screen
libcamera-jpeg -o test.jpg
Takes a single picture with the file mentioned.
And a 10 second video:
libcamera-vid -t 10000 -o test.h264
Note I did not have to enable, add or install any software. Not even the legacy mode in the command line raspi-config.
What it does mean is that if you have legacy software that does use raspistill then it won't work and will need to be rewritten.