You shouldn’t lose the two kits if you disconnect / reconnect Strava from Zwift. I was recommended to do that by Strava Support a few months back to fix a problem with screenshots and when I reconnected, the next ride saw me awarded the third Subscriber kit but I still have the other two kits in my garage as well.
I agree with the above posters that the original two kits I think are no longer available as new rewards since Strava changed their subscriber model a few years ago - if you got them back under their old model then you keep them but otherwise you can only get the new jersey now.