What kind of mindset should I have to stay in Bitcoin?
This kind of mindset:
I personally don't want to invest in other coins, as I think bitcoin is superior.
And I think Bitcoin is about to hit the highest price ever, so how should I plan my dca strategy?
If you think BTC is going to hit a new ATH, DCA isn't the perfect strategy, because it will take a long time until you invest a considerable sum of money in BTC. If you have larger amounts of funds right now to invest, don't wait too long to purchase BTC and don't invest in low dosages, rather buy and accumulate the maximum you can in a safe wallet you have total control over your coins.
But remember: I'm saying this in the scenario you mentioned, that is Bitcoin close of a new ATH soon. However, if your budget to invest is limited, do DCA as usual. It's better than nothing and the best you can in your currently conditions. Just take it easy with your investment not asking too much from yourself, as you had the world over your shoulders. Do your part and expect for the best.