searchmine, bing, and mycouponsmart have cropped up on my mac. please help me get rid of them.

a similar question from 07/19 has been closed (https://discussions.apple.com/thread/250482284), so i am asking again.

i am running high sierra 10.13.6 and chrome 78.0.3904.108.

a mycouponsmart extension, not from the chrome store, has appeared on my mac, and the chrome extensions page gives me no opportunity to turn it off or remove it.

searchmine has replaced google as the search engine and drives searches from the address bar to bing.

the only way i can avoid this is to go to google.com and enter my search.

malwarebytes found, quarantined, and removed malware twice, and finds no more after running several more times. but the problems remain after restarting the mac.

what should i do?

in the 07/19 question, eric root advisedt:

"For Malwarebytes, it may be necessary to run more than one scan. After scanning a couple of times, restart the computer and test. If necessary, follow the manual instructions. Do not download any other programs that are listed in the articles. Malwarebytes uninstall

https://www.2-spyware.com/remove-bing-redirect-virus.html

How to get rid of Bing.com Redirect - Virus removal guide"

i don't understand his advice that i have made bold. follow what manual instructions? when he said not to download any programs that are listed in the articles, did he mean spyware.com/remove-bing-redirect-virus and https://www.pcrisk.com/removal-guides/9633-bing-com-redirect that he listed at the bottom of his comments? or did he mean to use them?

should i use them or/and something else?

those are my questions. what should i do?

thank you. i never thought i would be in this situation on a mac!