For your Sony a7 III, focusing on portraits, events, and weddings, I highly recommend the Godox V1-S Flash. It's perfectly compatible with Sony, offering a natural and soft light ideal for flattering portraits and dynamic event settings. The V1-S is part of Godox's wireless system, allowing for easy off-camera control, crucial for wedding and event photography. Its quick recycle time, powerful output, and TTL compatibility with the a7 III ensure you capture every moment perfectly. Additionally, the V1-S's impressive battery life and durable build make it a reliable choice for busy photographers. It's a great blend of performance and convenience.

Get Godox flashes, they are affordable and covers most needs.

If budget isn't a big issue, I'd recommend the Profoto A10 for the ultimate in quality, reliability and integration. But the Godox V1 gets you 90% of the way there for a fraction of the cost. And the Sony HVL-F60RM2, while expensive, pairs perfectly with Sony cameras.