An interim CTO covers leadership
An interim CTO is temporary technical leadership while a full-time CTO search runs. A fractional CTO is that same leadership on a part-week schedule. Either person sets direction, reviews architecture, and keeps engineers unblocked.
Name the decisions that cannot wait this week. Ask a leader who has already run engineers to cover those decisions. Agree the days each week, the decisions they own, and how you will reach them. Tie the end of that coverage to the full-time CTO search.
To hire fractional CTO leadership, talk with people who have led a team and can explain architecture they owned. Agree pay with that leader directly. That agreement is separate from an Arca.ph introduction, so the 15% fee does not apply to it.
How to hire a CTO
How to hire a CTO is a slower search. You are looking for a leader who will own the team, the architecture, and the hiring bar. Talk with people who have done that job. Ask them to walk through a hard decision they made and what they would change.
Keep the engineer search moving while the CTO search runs. The product still needs people who can ship. Hire those engineers now, on a parallel track.