Profile Sync Daemon (psd) moves browser profiles to tmpfs, reducing disk I/O and speeding things up. It ships with support for a number of browsers, but Brave is not always among them. Fortunately it is easy to add.

Browser support files live in /usr/share/psd/browsers/. Each one is a small shell snippet that tells psd the process name and profile path for that browser. Create one for Brave:

$ sudo tee /usr/share/psd/browsers/brave << 'EOF'
# Profile-sync-daemon browser support for Brave

DIRArr[0]="$XDG_CONFIG_HOME/BraveSoftware/Brave-Browser"
PSNAME="brave"
EOF

Then open ~/.config/psd/psd.conf and add brave to the BROWSERS array:

BROWSERS=(brave)

Finally, restart psd:

$ systemctl --user restart psd

You can verify it is working with psd preview, which should now list Brave among the synced profiles.