For choosing the next one, the questions worth asking in order:
Does it export, and what? Look for a documented export before buying, not a promise of one. Check whether it is raw or summarised.
Is there a documented API? If a third party can read your data with your permission, you are much less trapped.
Does it sync to a platform health store? If the data also lands somewhere you control, the company's app becomes one view of your data rather than the only one.
Are the formats standard? Activity files in the common interchange formats are readable by everything. A proprietary blob is not.
Does anything work without the cloud? Some devices are useful offline; some are ornaments the moment the servers stop.
Is a subscription required to see your own history? This is increasingly common and is worth knowing before rather than after.
The honest summary of the category: the sports-focused brands tend to be better on export and standard formats, and the lifestyle and ring products tend to be worse, because their value is the interpretation rather than the numbers. That is a trade-off rather than a verdict: but if portability matters to you it is a real difference and it is visible before you buy.