I'm a freelance writer. In my service categories, I chose the article and blog writing option in the first place. Now, it doesn't have this option. It shows other options like web content, content and copywriting etc. Also, the COVID-19 option has been removed as well. I've checked but couldn't find that option.
When I choose the article and blog writing option, it shows the jobs related to this field only on my job feed.
For your first question, I can confirm that once you've deleted a file on your end, it's deleted on your client's end too.
As for your second question, you have Web Content, Content & Copywriting, and Creative Writing in your chosen Categories (Settings > Profile Settings > Categories). You can update this by going to your Profile Settings page or clicking on the "pencil icon" under the "My Categories" section on your Find Work page. This will remove the Web Content category from the jobs you offer, and will also remove the jobs related in this category.
As for the COVID-19 job feed is no longer live as noted by Lena here.
If there's anything else our team can help you with, please let us know by updating this thread. Have a nice day!