Need expert to replace a toilet flush valve and install new chain

I'm looking for a reliable handyman to replace a faulty toilet flush valve and install a new pull chain/flush mechanism in my bathroom. The current unit leaks occasionally and the toilet sometimes runs after flushing. I prefer a quick, tidy job with minimal disruption. Please bring the appropriate parts or advise on compatible options, and ensure proper resealing and testing to prevent leaks after completion. Located in a ground-floor bathroom; access is straightforward. I’m aiming for a clean, professional finish and a short troubleshooting session if any leftover issue arises.