What @JammyDodger is saying is correct, these are purposeful UX decisions, we want saving a bookmark and setting a reminder to be as frictionless as possible.
Because you can edit the bookmark to change the name, time, and auto delete options.
This is because the passage of time in most cases for these prefill options makes it impractical to preselect the original option. For example if you choose Tomorrow then wait a day and open the bookmark to edit it, we would need additional logic to figure out whether you chose tomorrow today or some day in the past and preselect the correct option accordingly. Multiply this across all our preselect options, and it’s just easier to bring it back as custom.