Windows by default cannot read Mac-formatted hard discs, hence the suggestions about reformatting them before use to a common format that both can read (FAT or FAT32 usually). But as you say, in your case it isn’t quite what you want as it will lose the data involved.
There are some software options that you can install on your Windows machine which may allow the HDD to be accessed. One of the most common is HFSExplorer, which I think has a free version that will allow read-only access. Another is MacDrive which has a free 5-day trial option.
Either of these may or may not work for you, but it’s something that you could try to at least allow you to pull your files from your drive so you can then reformat it either to FAT32 (if you need dual Windows/Mac access - note this has a 4GB individual file size limitation) or NTFS (if you now only need Windows full access - Mac’s can read/copy from NTFS, but not write to it iirc). Please note that I haven’t tried either of them (and have no affiliation with either) as I don’t have a Mac, but it may be helpful for you or at least something to try.
