I think most wont do it anymore.
Do you have a friend or colleague that could do it? You’ll likely find people are very flattered to be asked.
Unfortunately, none of the British people I know have jobs on the list of approved occupations. I'm not sure how to find out whether anyone I know is suitable.
I found this information, from here:
https://www.bathnes.gov.uk/sites/default/files/siteimages/Births-marriages-deaths/Citizenship/faqs_regarding_the_british_citizenship_process1.pdf"The list is not an exhaustive list; therefore an individual’s profession may not be listed as acceptable although they may fall under the category of a person of any nationality who is of professional standing or a member of a professional association. If the caseworker is not satisfied with your referee they may request another."
I'm not sure what counts as a person "of professional standing" apart from the jobs they've cited on the list. Do you know how they make that decision?
Also, my flatmate is British, but I know you can't have anyone living at the same address as you to countersign your passport, so I wasn't sure if the same would apply here - does anyone know?