To find your empire save look in the saves folder (usually "Documents\Paradox Interactive\Age of Wonders Planetfall Saves") for an AEG file. Open the save in a text editor and verify that it is the correct empire by looking for the name of your empire near the beginning of the file.

Once in your empire save search for either the first name or last name of your hero. If you can't find the name as readable text this could be because the name has apostrophes or just because. To try to fix this, randomize the name of the character in game and change it back afterwards.

Once you find the name, all of the hero's perks should be readable shortly after said name (sometimes this doesn't happen but being readable doesn't affect much). Before each of the perks there is a bunch of special characters and an id in the form [#0000039F00000E??]?\?????? where the question marks before the ending bracket are the perk id and the question marks at the end may be special characters.

The secret tech and race use the same format but with 39A (or 385, 386, 3E0) and 357 (or 341, 3DA, 3E0) instead of 39F. The secret tech should be the first id after the name while the race is the 9th id before the name. I recommend using a hex editor for this part to make it easier to write the special characters. To change the tech/race look up the tech/race you want to change it to in the below tables and copy it into the file. You should also look up the tech/race you currently are to verify that you are changing the correct field.

You could also change the perks this way but there are so many and I didn't want to make a table for them but you can create a hero with the desired perks and copy them over.