Just catching up on this thread and honestly, @Reply #2 - good point! You really can't escape the official brick if you want those crazy speeds — it's annoying but that's proprietary tech for you. But look, everyone keeps acting like you have to stay in the OnePlus ecosystem for audio and I think it's mostly hype. I mean, the 'integration' is just a menu in your settings — you can get way better value elsewhere. I'd actually grab the Soundcore Liberty 4 NC Wireless Earbuds instead — the ANC is actually better than the Buds Pro 2 in my experience and you'll save a chunk of change. Quick tip: make sure you're using the original OnePlus SUPERVOOC Type-A to Type-C Cable with that 80W brick; I tried a fancy third-party cable last week and — wait, no — it was a high-end PD cable and it still wouldn't trigger the fast charging. It's all in the proprietary pins, I guess.

Like someone mentioned, you must use the proprietary brick. I would recommend the OnePlus 100W Dual Port SUPERVOOC Power Adapter for better heat management than smaller blocks. For audio, the OnePlus Buds 3 are a prudent choice at $99. They provide the same ecosystem benefits as the Pro model but leave you more room in your budget. TL;DR: Stick to official OnePlus hardware to ensure safety and get the advertised charging speeds.

You really have to be careful with these high-speed charging protocols — I’ve seen too many people try to save a few bucks and end up with a warm phone that barely charges. Just make sure you double-check those cable ratings (it’s so easy to forget those), because without the right electronic handshake, your speeds will just crawl — wait, no — it’s actually about the long-term battery safety. I’d recommend sticking with the manufacturer's official gear.

The OnePlus 80W SUPERVOOC Power Adapter is mandatory for the speeds you want. OnePlus uses a proprietary charging protocol. If you use a third-party block like the Anker 715 Charger Nano II 65W, the phone will default to standard Power Delivery speeds, which usually peak at 18W. You will not get the 67W charging the Open supports without the official brick. For your $250 budget, the OnePlus ecosystem is the better choice:

• OnePlus Buds Pro 2: These cost roughly $150. They support LHDC 5.0 and integrate directly into the OxygenOS settings. You do not need a separate app to manage noise cancellation or firmware updates.
• OnePlus 80W SUPERVOOC Power Adapter: This costs $49. It is the only way to guarantee the 0-100% charge time in under 45 minutes.
• Total: ~$200 plus tax. In contrast, the Sony WF-1000XM5 retails for $299. Even on sale for $249, you would have no money left for a charger. While the Sony ANC is better, the Buds Pro 2 are more practical for your budget. Idk if this applies to every single GaN charger out there, but I have never seen a non-Oppo/OnePlus brick hit full SuperVOOC speeds on these phones. Stick to the official gear to avoid the slow charging you had on the S21.