Firefox on Ubuntu’s repository is now managed fully by Mozilla, while in the past it wasn’t. Mozilla has had a deal with Google for years to be the default search engine that has massively helped them stay alive as a company.
You are simply now getting an official build instead of a modified one, and official builds don’t let you remove Google from the main interface due to this contract.
There is a lot of misinformation regarding the security of older OSes.
There are some people online fabricating videos of older Windows (moslty XP and 7) “getting hacked in 5 minutes by idling”, with one of these videos even clearly having a web browser open in the taskbar with the title “virus download”. And when it is pointed out that this doesn’t happen, they get defensive that it will if you are raw connected to the internet. But pretty much everyone owns a modern router that would block direct connections by default, and most ISPs gift one even.
I have a Windows Vista VM that I use to play period correct and older games, even online. ClamWin is installed, OS is fully updated via LegacyUpdate and a modern browser (r3dfox) is used. There is nothing wrong with it despite hours of use, and I can keep playing with the huge nostalgia bonus of having the VMWare graphics overhead match pretty spot on the performance of a mid-range PC of the time on my hardware.
I will never let go of the 2010s