Sidechains cant have BTC as a native currency. They all are their own token even if named similarly and with 1 for 1 pegging like Liquid or anything else built with Elements. Drivechain is a different approach than peg-in/out that Liquid uses but it still has a process to get into and out of that sidechain. But instead of dealing with a discreet federation, its vetted by miners via hashrate escrows. Theres a limit of 256 slots making them rare and they can only be facilitated by miners. A normal user can not make or manage their own sidechain with drivechain. Its a centralized permissioned protocol.