Different sites report different blockchain sizes. Some of that might be explained by base-2 or base-10 sizes, but that's not enough to explain the large difference between the extremes.

Is there a site that accurately reports in bytes both the raw size and Core's on-disk size (without the UTXO set)?

201.57 GB (= 187.72 GB² if it's GB¹⁰) - BitInfoCharts (block 527,582)
178.99 GB (= 192.18 GB¹⁰ if it's GB²) - Coin Dance
171,292 MB (= 179.61 GB¹⁰ if it's MB²) - Blockchain.info (updated once per day)
161.20 GiB (= 173.08 GB¹⁰) - Bitcoin.com