But we don't have anything like FF as an alternative to go from Android. Especially considering banks require "certified OS".
We previously tried to work with a much smaller company which was a startup and ended up going bankrupt. The current partnership with an OEM is a new thing entirely separate from that and it's not a small company or startup.
Our requirements are listed at https://grapheneos.org/faq#future-devices. The devices we're working on with this OEM will meet these requirements and provide an alternative to Pixels for GrapheneOS. They may not initially be quite on the same security level as Pixels, but they will provide what's listed there and can get better from there.