luckylinux TBH I'd probably go used 7Pro. 7a for 300 EUR seems like a rip off. In terms of flashiness, sure, new Xiaomi/Redmi will come with more Mpix and brighter screen, but also builtin backdoors, so you decide what you prefer :)
No one here would say that in the absolute terms these brands have trash hardware (after all almost all our phones are made and assembled in China!), but the difference is in the architecture (I'm certain many of GOS users would love to have a choice of hardware, I would), and security support.
If brands like Sony can stop supporting flagships less than 2 years from release, they're not a viable choice.
If a vendor doesn't provide firmware updates, they're not secure.
Pick your poison.
PS. Maybe just get a beaten 6 Pro until you save for 8 Pro / 9a or so? You can get it fairly cheap and it's still a brilliant piece of hardware.