What I actually do on a team
Take a slice of the roadmap and own it end to end: schema, queries, queue jobs, tests, the deploy. I write the migration and the rollback, and I read the code around a change before making it, which is usually where the real bug lives.
Where I am worth the money
Legacy Laravel that nobody wants to touch. N+1 queries and jobs that silently retry forever. Upgrades that stalled two majors ago. Test suites that exist but do not catch anything. These take a specialist longer to explain than to fix.
How the arrangement works
Hourly or a monthly block, billed fortnightly against a shared board. Your standup, your branch naming, your review process. Notice period is a fortnight either way so neither of us is trapped.