Ark works under a very specific set of conditions, otherwise it's just a waste.
nostr:npub1h8nk2346qezka5cpm8jjh3yl5j88pf4ly2ptu7s6uu55wcfqy0wq36rpev in relation to episode #761
I'm guessing there's some lead time between our chat and new episodes, and you are still researching. But ARK is an idea on paper. Several other ideas thrown around that are the supposed answer to why we won't/don't need Drivechain are also in very early development.
DriveChain has activation ready code with zcash, eth and lightning sidechain code writen ready to go.
Discussion
One of those conditions happens to be custody by someone else.