I tried variety on my channels when Nightingale was around, but it didn't work, I was losing my usual audience. With the limited time I have to make content, I have to focus on my channel's usual topic.
I have a secondary channel for music related content, but not being able to link multiple channels is an issue. Currently the only option would be to change which channel I have linked but this causes problems, what if there are multiple rewards running and I would like to post to both and they would require the two different channels? But even if I would do submit wait until I get rewarded then change the channel and submit to the other one, if someone looks back on those reward submissions the channel wouldn't show up as verified, so they would then question why it was rewarded. So I don't want to do this, have to make a pick which of my channels to link.
I think the other problem is a lot of rewards are asking for new content. And you might have a recent content on your channels which would fit perfectly but you can't submit it, so need to produce a new one. I think this goes against one of the original ideas of the site, where it was about being able to share the content you do anyway and get rewarded for it, rather then making content asked for specifically for this site even though the content is hosted somewhere else.
So since there's very rarely something popping up in my niche which I can freely post on my socials without risking to lose my viewers the way I look at rewards is as commissions. So they are asking me to make this content. How long does this going to take me to make, how much I can potentially get paid for it, is it worth my time investment and putting it on my channels knowing that my submission might even not get rewarded, so then I effectively made this piece of work for free (since my channels are not monetised).
So unless the reward is related to my usual content and it benefits my own channel, I mostly just submit to text rewards if the topic interests me, but we have seen less text rewards lately.