specify a policy for allowing access to a table through a foreign key

Question

Consider the following two tables in a PostgreSQL database:

create table if not exists public.users (
  id text primary key,
  is_staff boolean
);

create table if not exists public.issues (
  id int primary key,
  issue_owner text not null references public.users on delete restrict
);

alter table public.issues enable row level security;

I want to create policies that will ensure only the owner of an issue and staff members can access the row.

Here's my current attempt — the only way I have been able to make it work is with a subquery:

create policy "Issues are accessible to their owners."
  on public.issues
  using ( current_user = issue_owner );

create policy "Issues are accessible to staff members."
  on public.issues
  using (
    exists (
      select 1 from public.users where current_user = id and is_staff = true
    )
  );

This works exactly as intended but I am wondering if there is a more efficient way to do this. By "efficient", I am considering both performance and readability.