I stopped using Compact, because it introduced a noticeable lag on NVME, like when opening Settings or Explorer. I had a laptop with 32GB eMMC, it was an atrocity, it seemed slower than HDD. You will age several years trying to deal with it. My system partition was 64GB with 30GB free, yet windows updates failed sometimes and upon a clean setup, I used to have 500MB free. So 52GB is merely theoretical, you need 100GB+ to be free of problems. I have 128GB now, 25GB used.
So I guess you were using the standard command on your NVME drive, hence Xpress 4k? What kind of CPU does it have? How much RAM? 24H2? Which device of yours would be the one with the 32GB eMMC? The loading times, the lag can be way worse on such old machines. Up to unuseable. Already without using compact. Yes, it is close to anoying here already. Yet Im suprised how well this device works together with 24H2, compared to other CPU / RAM / SSD combinations. I wasnt expecting this Lenovo laptop to become way faster because of compact. I just needed more free space. This lenovo failed on youtube (4k) playback in 2017 already. 32GB of eMMC is a joke for sure in 2026. But having 10gb of free space instead of 1gb does indeed make a little difference on this typewriter. Just for fun I used the LZX command (should only be used on rarely used files/folders) inside of the Forefox folder: (632mb to 325mb) compact /c /s /exe:lzx Firefox is slow now. Slower than before. But its still okay.
compact is NTFS native compression, compact /compactOs:always adds another layer of higher performance data compression by singling out, deduping, etc. Using both is discouraged on the volume level but you can apply compact on a per folder level (another post mentions Firefox, fine example but LZX is essentially the max, so performance penalty is significant—your 4k-8k is better) like Program Files to get the best of both. I do it routinely on small lab vhdx’s.