The impression I took away from the Q+A is that it will be removed as a new download from the marketplace but it won’t suddenly disappear from your simulator if you already have it.
Obviously if you do a new install of the sim for whatever reason it’ll no longer be available. You won’t loose the F-18 since that wasn’t part of Top Gun DLC but you will loose the Maverick livery for it.
Personally I’ll be sad for the Darkstar not to come to FS2024 later this year. I know its a fictitious plane but I’ve always had a lot of fun with it.