Xiaomi - Mi Band (1st Generation)

Some are kinda decent if you just want a basic fitness band with notifications and music controls. There are some decent brands that make them, like Haylou, Xiaomi, Amazfit, etc. However, what I see with these more basic smartwatches (had experience with Miband), is that their notifications capabilities are much less robust than WearOS. That was the primary reason why I upgraded from Mibands to a Galaxy Watch.

Just buy a miband from Xiaomi

In my 2500m sessions it can seldom skip 25 or 50m tops but I guess I could say it's reliable never had any issues. It gives average pace, best 100m pace, number of strokes per lap. You can define the pool size too.

Get a mi band, I’ve had a couple of them over the years and they work great with iPhones as well.

I've used "Mi Bands" (Xiaomi Smart Band) for the longest time, fundamentally for Step Counting and Sleep Tracking, rarely as a bluetooth remote control and for NFC payment. It's very small and unintrusive, doesn't bother you at all and it only needs charging every two-three weeks. You don't have to use all the unneccesary bells and whistles obviously.

I tried the MiBand. I found it very inaccurate so I ended up not using it