How can I get a 60-day visa extension in Thailand after my tourist exempt visa expires?

There’s no such thing as a bias agent. They’re working to make money for themselves. It’s of no benefit to you.

What do you mean they moved the office to 8km .???

If you entered on 60 day tourist visa you go to chaingwattana government building for your extension .

How ever you more and likely be asked to do 30 day extension first if you haven't done one yet before you get 60 day extension due to covid

If you haven't gotten your regular 30 day extension yet, they will likely make you do that first.

Visa agents aren't very useful right now if you're hoping to get an under-the-table visa. They rotated all of the upper level immigration management around the country so the visa agents aren't doing the brown envelope visas right now.

If it's a Visa you qualify for but are just too lazy or can't be arsed to do it yourself, they'll gladly take your money to do what you can easily do though.