i was wondering how the process of restoring funds with the 12 word phrase does work
on a newly installed BRD-wallet (on the same Android device)….
For Android devices
It is clearly stated immediately you launch the wallet after download at the lower part at the center you will see 'restore wallet' just like other noncustodial wallets.
Does that mean the the old 12word phrases are not anymore valid for this new wallet
and can only be used for restoring the funds?
Your seed phrase is always valid, so far you have it, you can use it to always restore back your wallet and your balance will reappear and accessible for you to make use of.