I used a series of Fitbit watches with my SE1 (2016) and my 8 Plus before I got my AWs5. They were not as good as Apple watches, but were not that bad, either. The last Fitbit I used was the Versa. They're pretty sharp and are substantially less expensive than Apple Watch. https://www.fitbit.com/global/us/products/smartwatches
That was my experience too -- the Versa worked well enough that it whet my appetite for a real smartwatch, and I ended up with the Apple Watch series 5. Apple Watch is better than Fitbit not because Fitbit is bad - but because Apple Watch is that good. ?I had been a long time Fitbit user too - but more their basic bands. Ironically the Versa, when it’s time to was up, convinced me that a smarter smartwatch might be useful.