Try to flash Magisk. Works for me !
I bought the A6 today, followed the steps here in BlackMesa's first post.
TWRP installed successfully. I flashed both ZIPs (latest no-verity-opt-encrypt and RMM Bypass).
Result: The phone was stuck in a bootloop. However, I was still able to get into TWRP with the normal button combination.
First, I panicked and I thought I must download stock firmware and flash it to recover my phone. But then I read here in the thread that the additional flashing of Magisk should fix the bootloop.
So I downloaded the latest Magisk v18.0, put it to my external SD and flashed it. And YES, the phone boots again, everything works and I have root!
Thanks a lot guys, you are great!
BlackMesa:
In your very first post in the installation guide, you should really add one additional bullet point:
"Install the latest Magisk 18.0, otherwise you are stuck in a bootloop."
This will probably help many other users in the same situation and avoid people from panicking and flashing stock firmware again.