Ecosia is an application.
Finder > Applications > Ecosia
You can right click move it to the trash.
If you see an uninstaller app run it.
Try these two apps. Hopefully
You can remove adware/malware using either Malwarebytes for Mac or EtreCheck.
1. Using “Malwarebytes for Mac”:
Use the latest release of MalwareBytes for Mac to remove malware/adware.
Install guide: https://support.malwarebytes.com/docs/DOC-1817
Uninstall Guide: https://support.malwarebytes.com/docs/DOC-1190
The installer may ask you to allow it in Security & Privacy /System Preference. Allow it.
Click the “Scan Now” button. Once done quit Malwarebytes for Mac.
Restart the computer, relaunch Safari holding the shift key down.
2. Using EtreCheck: https://etrecheck.com/maspro
Click the “Free Download” and then“Click to Download” button.
Open Downloads folder, click on it to open, and then select ”Open”.
Click on the bouncing EtreCheck icon in the Dock.
“Choose a problem” from the popup menu box, and then “Start EtreCheck” in the dialog.
Scroll up the sidebar and click the “Security” button.
“Adware” and “Unsigned” files will be listed on the right hand side pane along with a “Remove” button.
Click the ”Remove” button wherever you see “adware”.
Restart your Mac. Launch Safari holding the “Shift” key down.
Take the steps 2,3,4 and 5 listed under "Additional steps"
Additional steps, if necessary.
1. Remove unknown and third party installed Configuration Profiles. https://support.apple.com/kb/PH25680?locale=en_US
2. Remove unknown and third party installed extensions. https://support.apple.com/guide/safari/use-safari-extensions-sfri32508/mac
3. Reset search engine. https://support.apple.com/guide/safari/customize-your-search-ibrwe75c2a3c/mac
4. Reset Homepage. https://support.apple.com/guide/safari/set-your-homepage-ibrw1020/mac
5. Restart the computer, relaunch Safari holding the shift key down.