Pivoting a 6-year-old channel to a history podcast

I run a history channel that is technically 6 years old, but for the first 5 years, I constantly changed my niche. Three months ago, I finally locked into the specific niche I am deeply passionate about: deep-dive history and podcasts. Since the shift, I have uploaded around 20 videos and have an audience base of 1,364 followers.

Here is my background: I actually had my channel qualified for the Partner Program about 1.5 years ago. However, I completely stopped uploading videos because, honestly, I got lazy. When my channel was removed from the program due to inactivity, it woke me up and forced me to regain my drive. Before restarting 3 months ago, my historical baseline retention was 65 hours. Since uploading these 20 videos, it has grown to 110 total hours. I know the default threshold to re-qualify is steep, and I need to accelerate my growth.

My major goal before the end of this year is to start inviting high-profile authors in the history field onto my podcast. I initially thought about waiting until I reached a default 4-to-5-digit baseline reach, but I realize I need to start pitching now to achieve the goals I am aiming for.

For creators in the educational or interview space, I would highly appreciate your tips on:

1. Gaining Views & Reach: What strategies work best in the history niche to break out of low view cycles and get pushed by the algorithm?
2. Accelerating Retention Hours: What structural video formats, hook techniques, or topic selection styles work best to keep history viewers highly engaged so I can stack up watch hours faster?
3. Networking & Pitching Big Guests: How do you successfully approach established academics and major history authors when your current baseline reach is still small? What value can a highly dedicated, smaller platform offer them?