That would be an indirect way to add a "bounty" for a feature, which we don't do.
If people want to donate to the project, they are free to do so, but the priority of what features will or will not be implemented is ultimately up to the team, and that will not change, and will not be influenced by donations.
The problem with "throwing money" at a specific feature you want to see implemented is that even if it was implemented, and even if it was done in the "GrapheneOS way", and even if our team had the bandwidth to review that change to ensure that it has to be merged, every single change that's added that deviates from AOSP has to be constantly ported over to new versions with every monthly, quarterly, and yearly release, with the 2 latter being the more significant burden.
In other words, every feature we add, is another we do not. We are aware that there are things that need to be implemented, and a lot of what the community might want, the teams wants as well, but that can only be done when the time is right, and no amount of "bounties" towards that feature will ultimately push it up the list, as feature development is prioritized based on what is needed at the time, and those priorities also constantly change based on various factors.
While I appreciate the brainstorming and willingness to help push things forward, and perhaps even your financial contribution towards those features if what you're proposing were to happen, there is no such system for a reason, and it wouldn't work for us.