Flicker is often the result of a fluorescent conversion that did not remove the ballast.
Flicker is more a failing LED bulb .
I’ve experimented with all the energy saving types. Some CFL failed in weeks,some brands still bright and steady after 5 or more years. Just replaced the last CFL in use with LED.
Really annoying is I pay $32 “access” monthly before using the first kwh.Seriously considering alternatives.