> Also - can one access certain Mac folders in Asahi (e.g. ~/Pictures)? And is it even recommended, if it's possible (Security wise)?

You cannot access any of your Mac folders in Asahi. Your Mac partitions are invisible until you reboot into MacOS.

Some potential workarounds:

1. Use Syncthing to sync your Pictures folder on both operating systems to an external Mac. This of course duplicates the contents of the folder on your Mac/Asahi SSD, which is wasteful.

[Note: Dropbox does not work on Asahi Linux because it only barely works on x86 Linux and it has never worked on Arm Linux.]

2. Use an external USB or SD drive for files you want to share. Needs to be formatted in something both OSes can read/write (e.g. not APFS).

3. Use Paragon's $40 extFS which lets MacOS read and write to your Linux partition. Supposedly; I haven't tried it. This only solves half your problem: It gives MacOS access to your Linux files but not the reverse.

https://www.paragon-software.com/home/extfs-mac/

What's really needed is a way to mount APFS partitions from Linux, and I plan to DDG that as soon as I finish typing this...

UPDATE: APFS FUSE seems to be recommended, although it only provides read access to your APFS partition.

https://github.com/sgan81/apfs-fuse

4. Make a brand new partition on your drive for shared files, and format it exFAT. MacOS can read/write exFAT natively and Linux can usually be made to do so, although I haven't tried it yet on Asahi. This seems to me like the most promising option if you don't want to depend on an external drive.

UDF works for both OSes.