Molocoto Nothing is generally doing bimonthly updates, so your 3a should get an April update - most of the time these security updates are rolled out by the second half of month. Even though April is almost over, it might still be possible to see an update next week.
Another reason: Since it is a new device, Nothing has mostly concentrated on pure bug fixing and improvement updates, both the regular and Pro 3a will still be scheduled into the actual update cycle, since these phones have just been released recently.
