It's not normal for personal files to change access date/time unless they are accessed somehow ... Although browsing a directory with some applications e.g. email client attach dialog might indeed change access date/time which is especially known for file-types like images and videos that are previewed as thumbnails.
However, who or what had accessed a certain file is not per se logged by default ... There might be traces in some specific applications' logs generally for system files and not personal files and that's it.
Bottom line is that unless you have auditing service on and active for a certain file/directory, there is no way for knowing who or what accessed the file.
You can setup auditing like so:
sudo apt install auditd
Then, start monitoring a file like so:
sudo auditctl -w /path/to/file
Or a directory(be careful with auditing directories as the logfile size might grow extremely large especially for Home) like so:
sudo auditctl -w /path/to/directory/
You can list currently audited files/directories entries like so:
sudo auditctl -l
and delete those entries like so:
sudo auditctl -W file/directory
The audit information will be written to the file:
That you can view and search with e.g.:
grep "something" /var/log/audit/audit.log
or with e.g.:
ausearch --file "file-name"
and get reports with e.g.:
man auditd - The Linux Audit daemon.
man auditctl - a utility to assist controlling the kernel's audit system.
man ausearch - a tool to query audit daemon logs.
man aureport - a tool that produces summary reports of audit daemon logs.