FYI I wrote code to make Unity not lose save data when you publish updates and the source code is freely available.
If you're using PlayerPrefs, this would be the easiest implementation
https://3p0ch.newgrounds.com/news/post/1086279
and check puetsua's and IncontinentCell's comments at the end because I wrote that a couple years ago and maybe Unity updates since then have made it need tweaks.
If you're not using PlayerPrefs but you have the save data in a single structured object (or can get it into one) then you can use/cannibalize the Unity implementation of code I originally wrote to make it so multiple game devs could run a multi-game collab and just use it for a standalone game, which also prevents save data loss when you publish updates
https://3p0ch.newgrounds.com/news/post/1099579
If you incorporate either of these implementations then the save data will be wiped when you publish that update, but for any more updates in the future it will persist.