This all depends on your income targets.

Tip: If you're looking for highest rates, you'll avoid new grads like the plague. They have no experience, so you're talking about competing on price.

For example, I work as a Fractional CTO... charging... well... a massively high hourly rate + percentage of profits.

Agencies who pitch my services have very little competition + the rates they're targeting are stratospheric, compared with new grad rates.

Tip: Start with your income requirements + amount of work you can tolerate. Also client quality you'll be working with + applicant quality you'll be working with.

All these factors set your marketing.

Tip: All the marketing you've listed above leaves you competing with every other similar company on price, so you'll work as hard as everyone else, have very little repeat business, with lowest possible profits/engagement.

Look for marketing venues with zero competition.

For example, speaking at https://Meetup.com groups or other events related to your niche.