The best way to see if you're doing your seo "wrong" in my opinion, is to look at your analytics and then look at your search impressions.
You say your thumbnails are great, but personally without looking at your CTR, there's work and refining you need to do (high CTR indicates that indeed your thumbnails are probably great (mixed in with great title, and great topic) but if the CTR is low, that indicates people aren't clicking, meaning your thumbs aren't hitting the mark, or it could be your topics. Typically I'm now finding it's topic that's the biggest problem with videos)
If your search impressions are high (we're talking in the thousands of impressions) and your CTR is low, it means your SEO is actually doing it's job, your SEO is putting your video in front of POTENTIAL clicks. It's up the the viewer from that point on to decide if your thumbnail is worth clicking, or your topic is worth clicking.
I find that it tends to be thumbnails that are people's issue rather than SEO. I suspect your search impressions are probably high, and that your ctr is probably low.
With your style of thumbs, there's a LOT going on, you're trying out a million differant fonts and colours, which ultimately results in a really messy, cluttered gallery of thumbs that can tend to throw people off.
What does roller skating have to do with Whiskey?
What's 90's pop culture got to do with whiskey?
What's batman got to do with whiskey?
I can't tell if you're supposed to be a whiskey channel, or a pop culture channel? Can the two be blended together like you're trying or are you trying to do too much? Which then goes onto the issue of Topic.
Even the best SEO can't save a topic people aren't interested in. I've experimented with trying some topics that are outside of my norm while staying on niche, and over the last 2 year I learned... you can't force people to be interested in what you make... you have to make stuff people are interested in watching.
Like... on face value I like what you're doing, but there's also a LOT going on which clutters your message, and if I were only into pop culture, why would I want to watch videos on whiskey? Or if I'm interested in whiskey... why do I care about your thoughts on differant pop culture? I know there's channels that do a bit of a "bar talk" or just "talking over the bar" and I don't know enough about niche or culture to know how to get that to work, but it just seems like there's too much trying to be done and there seems to be a lot of veins going spreading out everywhere in the hopes SOMETHING will hit, and in trying to find SOMETHING that will hit, by trying a bunch of everything, you lose out on the views.
I'd try to narrow down your focus overall, but again, you need to look at your search impressions. If the search impressions are there, than the themes and topics are fine, it's the thumbs that are holding you back. But if the search impressions are also low... you may need to do some more research on your topics and what people are actually looking for.
And another possibility, is your impressions are high, and your click through rate is high, but your overall audience retention is low. Low audience retention means your videos aren't going to end up in recommended, because the videos themselves aren't interesting enough to watch for a significant enough portion (a problem I have with my videos still) they all flow into each other. And it takes a long time to master. I've been doing YouTube for 6 years and I only now feel I'm starting to get a hang of some of the basics of SEO.
Just my 2 cents which looks to be 2 dollars of things to consider.
