Edit: This is a much simplified GUI startup (not boot or system services) application manager
gnome-startup-applications
The Startup Applications Preferences app allows configuring applications to run automatically when logging in to your desktop. This app complies with the FreeDesktop.org Desktop Application Autostart Specification so it will work even if your chosen desktop is not GNOME.
systemd-analyze blame
And
systemd-analyze critical-chain
~
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Adjust to your liking
Use the Strong button if your brewer has one.
Insufflate if necessary.