I'm glad you asked this question. Yes, writing about the same topic is totally fine as long as it's not a post clone.

Two years ago when I was gardening I wrote about my gardening ventures several times a month. I may even had mentioned the same thoughts in a few of them but they were totally new posts with new info and photos. There are some here on Hive who only write about very few topics.

The main thing is as long as it’s not the exact same post (duplicate) you can write about the same topics. 😉