Do what the Chinese did and fork Android.
The EU has enough tech talent to do it, but the political and managerial class lack both the strategic ability or the willingness to adequately reward the effort it would take, almost certainly preferring to, again, outsource the concern, and then be shocked Pikachu later.
Anyone doubting this should see how BMW think about their in car software. And that is for a supposedly premium product.
If the govvies (any govvies; there is nothing specific to EU here) drive that process of forking a large, powerful, universally used system you will end up with more surveillance, not less.
Because kids, because pornography, because terrorism, whatever. This is too powerful an option for control freaks to resist.
There's GrapheneOS. It's Canadian, not European. I'm not sure where LineageOS is from.
BMW isn't the EU government. Like I said, someone has to actually do it. BMW Actually Did It in a really user hostile way, and that's the best we have. Why is nobody Actually Doing It but good? Or why aren't we buying MNT products?