I read this book about 10-15 years ago, and believe it was an 80s-90s book. The premise was that soldiers/space marines were remotely controlled, and if they died, their operators woke up in a vat back on their base ship. The book ended with the main character being betrayed, and most of the clones vats being destroyed. I think it was around 300-400 pages long?
The most notable point of the book was that the soldiers were considered suicide soldiers, designed for suicide missions, as death didn’t matter.