I had an analogous arrangement. I would pop in and out, identifying/building high impact projects, in a mix of web dev, PM, and analyzing data.

I was usually available for brainstorming/chats during my sometimes months of off cycle, including at non-regular hours. I'm hopelessly neural atypical with on/off cycles of productivity and haven't found a way to make myself more regular.

I was paid as a full time employee despite my schedule, with a mutually agreed upon below-market offer in exchange for that freedom. USD 130k/y with full benefits and a much smaller than normal equity grant.

That arrangement lasted 7 years before moving on to new opportunities.