backup plugin that you use or a backup from your host can help
https://ww.wp.xz.cn/themes/twentyseventeen/ was the official 2017 theme edition and has been supported and updated for 8 years. The latest update was in November 2024, so there’s a pretty good chance that the 2024 and 2025 themes will be supported up to 2030 or beyond.
Look under Tools > Site Health to see if there are any anomalies.
