I'd say if you have a relatively clean phone such as a Pixel or another one with minimal bloat, and install a ROM that comes with all the google apps and everything, then the benefit is probably fairly minimal.

But if you do a degoogled ROM then it's a huge difference. Stuff like GrapheneOS, CalyxOS, /e/OS.

Or if you have a phone with a ton of bloat and additional crap added like Samsung or the many Chinese brands, then even a ROM like LineageOS with google apps would be a big improvement in where data is getting sent.

Please never speak like that again. It's always worth using a custom operating system such as lineage OS. You cannot let Google defeat you.

The open source community will defeat Google.

Daily driving /e/OS on CMF Nothing 1 for months now https://murena.com/shop/smartphones/brand-new/murena-cmf-phone-1/ with 0 tinkering, just bought it and didn't stop since day 1.

Check my post history for more details (as I discussed a bit more about it just days ago) but basically if deGoogling is important to you (which I imagine since you are posting on the privacy community) then yes, it's definitely the most pragmatic compromise if you genuinely need Android based apps.

That Google is attacking custom ROMs should tell you anything you need to know. Definitely continue using ROMs as long as possible and pray to holy GNU that linux on mobile will attain day to day usability until that fails. It's actually looking pretty promising on that front!

Buy a fair phone and put /e/os on it.