Be sure to read the footnotes and fine print disclaimer regarding that mention of up to 1,000 charge cycles.
Here's the fine print:
All battery claims depend on network configuration and many other factors; actual results will vary. Battery has limited recharge cycles and may eventually need to be replaced. Battery life and charge cycles vary by use and settings.
The general rule is that you can expect a Battery Health drop of about 1% on average for every 25 charge cycles.
293 charge cycles divided by 25 = 11.7%.
So, it would be normal to expect that your Battery Health would be in the 87-89% range at this point. You report it is at 90%, which looks to be in the normal range and a bit better than average.