It's impossible to de-google or meaningfully remove unwanted stuff from Smart TVs while keeping them usable for streaming purposes.

What you want to do is factory reset, don't connect to the internet, go into settings and turn off whatever you can, and then use a streaming box.

Yes it's an additional cost but it's BETTER. The processors and memory in those TVs are lousy, the apps are often sluggish, the experience is simply not great. Frankly the hardware was built not to be usable for you, they are data collection platforms that include minimal low quality streaming experiences in order to collect data. No software is going to fix that.

Want something that "just works" and supports all the major streamers? Get an Apple TV 4k. It's pretty private but importantly no ads, clean interface, powerful hardware. Is it maximally private? No. But it is easy.

Want to put in effort? You can get either a Dune-HD box (some have dual-OS without reboot where one is Netflix certified to get you full resolution while passing DRM checks while another is unlocked bootloader which you can install all kinds of things like Plex and Kodi on) or get some other Android streaming device of your choice (Walmart's Onn brand 4k devices used to be very good and cheap though you might need to check as I heard rumors the latest devices can't be unlocked).

You'll have a better experience on more powerful hardware and will never want to go back to the bad on-board TV experience.