I'll try to offer my perspective, but there is no guarantee it'll be of any use to you.
You are touching on a few things that sound familiar. I _struggle_ with repetition. Tasks like emptying a dishwasher or taking out the trash, to me, are like pure torture. No idea why. Now you can probably imagine what gratitude journaling feels like for me as well ;)
Another commenter mentioned the mantra as a technique (even espoused by various religions, though I'm not religious at all). The mantra is a way to simply take up space / time / focus. As I also mentioned, gratitude journaling simply doesn't allow you to think anything else for a moment and that, in and of itself, can be a relief.
I tend to play around with how I write these things down. Prose takes more effort. Changing the wording, and writing it from different perspectives can be a way to dedicate more mind-resources to it and also make it less boring.
Crucially, however, my ability to do this is supported by the other things I do. I have found that another concept comes in handy here, something I've come to call "avoiding zero-days". A zero-day is a day where I have not done a single thing that contributes to my health. E.g. I have not eaten healthy, I have not learned anything, I have done no exercise, I have done no work and I have ALSO not relaxed (see, the thing with my depression is that I won't really do anything. The tell-tale sign for me is when I stop enjoying video games. That's when I know I'm in deep. So literally getting myself to even play a video game is a win which contributes to a non-zero-day).
The reason I try to avoid zero-days is because ANY of the aforementioned things can give me that tiny positive push to accomplish another thing. Eventually, that can lead to a cascade of me achieving 2-3 positive things I'd like to achieve. And that can be the beginning of crawling out of depression for a while.
Another tendency of mine is to retreat into repetition (ironically, despite hating it) for comfort / safety / convenience / efficiency. So my mind kind of goes "I can score non-zero days by just doing one thing over and over". Take gratitude journaling. I'll be really tempted to not put effort in. To the point where I'll just write single words "exercise, training, sunshine" and be done with it. I start to try to cheat my own system.
So, I then have to remind myself to mix up the activities and see if I can pivot away from the obsessive component locking me in.
It's a never-ending cat and mouse game. That's all I can add from my perspective, not sure if that's of any use to you.