I avoid Ubuntu because Canonical has a history of going their own way alone rather than collaborating on universal standards. For instance, when the X devs decided the successor to X11 needed to be a complete redesign from scratch companies like RedHat, Collabora, Intel, Google, Samsung, and more collaborated to build Wayland. However, Canonical announced Mir, and they went their own way alone.
When Gnome3 came out it was very controversial and this spawned alternatives such as Cinnamin, MATE, and Ubuntu's Unity desktop. Unity was the only Linux desktop, before or since, to include sponsored bloatware apps installed by default, and it also sold user search history to advertisers.
Then, there's snap. While Flatpak matured and becoame the defacto standard distro-agnostic package system, Canonical once again went their own way alone by creating snap.
I'm not an expert on Ubuntu or the Linux community, I've just been around long enough to see Canonical stir up controversy over and over by going left when everyone else goes right, failing after a few years, and wasting thousands of worker hours in the process.
Companies DO analyze what you say to smart speakers, but only after you have said "ok google, siri, alexa, etc." (or if they mistake something like "ok to go" as "ok google"). I am not aware of a single reputable source claiming smart speakers are always listening.
The reality is that analyzing a constant stream of audio is way less efficient and accurate than simply profiling users based on information such as internet usage, purchase history, political leanings, etc. If you're interested in online privacy device fingerprinting is a fascinating topic to start understanding how companies can determine exactly who you are based solely on information about your device. Then they use web tracking to determine what your interests are, who you associate with, how you spend your time, what your beliefs are, how you can be influenced, etc.
Your smart speaker isn't constantly listening because it doesn't need to. There are far easier ways to build a more accurate profile on you.