Tag conversion is always a little mystifying until you go through it. One reason people like formats other than WAV is that the tags can be stored in the files.
I use J River Media Center for a player and it has the option to store tags in a separate J River folder or in the files or it both places and options to copy tag information from the file to the library and from the library to the file. I am not an apple user, so am not familiar with the tagging options on Apple, but you should look into them before choosing a play. If I remember correctly, WMP has little or no tag editor capability.
Bear with me, if you already know this.
A CD has almost no tag information beyond the album name and artist. When you rip a CD, the ripper (dBpoweramp in your case) looks up the album in an online database and fills in the main tags. You can see this by putting a CD in and call up the dBpoweramp CD ripper. You will see that there is little information therem, but there is an option to choose a particular album from the database to use for tags. Once you choose the album, tag information will be filled in. It is usually limited to basic tags like album name, artist, track name, genre, composer, date. Any other tags you have to enter manually.
For wav files, none of the tags are entered into the file itself. However, the artist, album and track are typically part of the file structure, usually with the a folder name for the artist, a sub folder for the album name and individual files for each track. Since you originally ripped with dBpoweramp, you should know your file structure. Add since you say you have not made any changes to the tags, the file structure should be able to provide most of the tag information on conversion.
If you batch convert your existing library, dBpoweramp can pick up the artist, album, track names from the file structure, assuming a format like I described above. However, once the conversion is done, you can go back and add them using the dBpoweramp tag editor which you can access from Windows Explorer and Properties. You can edit a single track or multiple tracks. I do not think dBpoweramp can do automatic tag lookup from its database except when ripping, but I may be wrong. Alternatively, you can have you player software look up additional tag information for its online database, which is what I do with J River.
The biggest problem is often the cover art, which will not be transferred. You neeed to go through and have dBpoweramp (through properties) or your player find the art on the Internet and pull it into the FLAC file.
Sorry if you already know much of that, but some of it might be helpful.
Probably the best thing to do is to try a couple of albums and see how it goes. It will take some effort, but it is certainly not as bad as doing the original rips.
Good luck.