Replacing manual GTmetrix checks is less about deleting a bookmark and more about moving a promise from someone’s calendar into a system with dates.
Map the ritual you have today
Who runs checks, on which URLs, how often, and where screenshots land? If the answer is “mostly the homepage, when we remember,” write that down without embarrassment. Migration fails when you pretend the old ritual was stricter than it was.
Move the system of record first
Pin the same URLs (or a saner money-page set) in scheduled monitoring. Run in parallel for two to four weeks. Compare surprises: pages nobody tested, regressions that appeared between manual runs, field data the ritual never showed. Then retire the calendar reminder for those URLs.
Keep GTmetrix for incidents and launches. The goal is fewer obligatory manual runs, not zero diagnostic capability.
Communicate the change
Tell the client what is now scheduled, what still gets a specialist pass, and where they can view results if they have a seat. Apogee Watcher is built for that scheduled layer using PSI lab history and CrUX when available. Use it to replace the homework, not to win a brand war against a tool your developers still need.