Selling access to your audience is what you're already doing with AdSense, but you can supplement that with sponsorships. This video brought to you BetterVPNSpace et al. You will need to see 50k+ views per video on average over 10 videos or 90 days to even start having the discussion with any real brands. Really they want 100k+ views. They do not want millions of views, generally. They want a "good deal" and major creators regularly know their value, so you can find a lot of sponsors once you hit 100k+ views per video, but they're also going to try to lowball you every time and you're going to do a lot of negotiating where they end up ghosting you. You can partner with sponsors for long term deals, doing 5 or 10 videos instead of just one off deals. You can offer brands the opportunity to sponsor entire segments or series, or create sponsored content that more integrated.
Selling yourself is usually the most common way people operate on Youtube, but it's rarely a majority of the money you'll make. This is Patreon, Kofi, Youtube Membership, Twitch Subs, etc etc etc. Anything where people give their money directly to you. It might be 25%, it might be 10%. If it's 50%+ you're probably selling nudes or otherwise highly controversial and not getting ads/sponsors. Typically this has tiered membership with escalating perks. You might offer bhind the scenes content or early access. You can do personalized shoutouts or personalized content for top supporters.
Usually it's a hybrid blend of these. You do patreon and sponsors, adsense and afflinks, and then a merch shoutout now and then when you don't have a sponsor. You might put products on your patreon, like access to your course about how to google snakes at a higher tier than your normal support, and then update it monthly to encourage people to keep subscribed and move up tiers. Perhaps you upload a sponsor-free version of the video to patreon because they pay for that. etc.