I hope you won't mind some anecdotal information, Isabel.

I have had two Galaxy watches, both of which are capable of reading both BP and HR, but also capable of rendering an ECG. In fact, my Galaxy 4 was almost five months old when the software update came for we Canadians and our watches were enabled to perform the ECGs. Before then, the Canadian government was reviewing the engineering and data before approving the release of the update to Canadian users of the Samsung watches. My latest, a Galaxy 6 (nothing wrong with the 4, but for some reason Samsung vacillates between a hand rotating bezel feature and not having one. I like the bezel, and the next new issue was the 6, so I snapped one up for 'future' enjoyment and wear), came with the software updated.
I had an ablation in July of '22. It failed. Three months later, while walking slowly with my toddler grandson, his chubby hand wrapped around my extended pinky, I went into AF. I activated the app on my Galaxy and let it do a reading, which it duly deemed AF. My electrophysiologist, bless his heart, actually wanted to see the readout, and asked for a download. I did it, via the phone app called 'Wear', and sent the pdf file to his office. He notified me that he accepted the result and would schedule me for another ablation, which was ultimately successful.

i can't speak to other watches, but have you investigated the Kardia? They've been around, are durable, reliable, and very good. They are not wearable...you use them like a smartphone, hand-held.

Now for my anecdote: when I was in the ER, after my first ablation failed, I kept glancing at my watch. It almost rolled it eyes and said, ''YESSS...you're still in AF...dammit!" And so did my wife who held out her hand and said, 'Gimme...!' I had to surrender My Precious. And it was the right thing to do. My point is, the watch can nanny you to death. AF begets AF....that's one of the field's aphorisms. You want it to subside and to go away. But glancing at a tell-tale every 30 seconds just keeps you on the treadmill of anxiety, too much information, and not much else to do about it. I don't know why you want a watch that can detect AF, but be warned that it might not be the best thing for you if you tend to have anxiety.