Its very simple, make it so that while its buy phase your satchel can only explode if you recast it. If you don't recast it you can pick it up with f like cypher's cage and killjoy's nanoswarm. If the round starts and you didn't pick it up then it's timer starts and it acts like normal.

This would allow you to still boost yourself before the round starts but can prevent the unfortunate miss click that might cost you the round.