ubuntu? No way.
Ubuntu is one of User friendly distributions have a good community and good support behind it but not known as safe or privacy focus distro at all.
It had many security problems during years.
Even there was scandals for Ubuntu . last one i know was "Ubuntu Spyware".
Mint could be a good choice for anyone new to this area to learn what gnu/linux is.
Among  the security focus distros the best choice could be tails as NeuroticFish mentioned above. has electrum wallet by default.
You can read more here.(https://tails.boum.org/) its just live distro and not recomended for newcomers.
And check all distros popularity here. (https://distrowatch.com)


Its not true. you could not,Can not, and will not be able to Secure windows Ever.