Do you have a brand store with multiple products in same niche OR a portfolio of products unrelated to eachother?

In 2024, Amazon is super competitive – obviously. So I’m at a crossroads of how to continue on Amazon. I have a successful one-off product. I’m currently researching next products but I’m trying to decide between building a brand around one niche with multiple products all under the brand or just doing product research to find one-off opportunities where competition is low.

If I do a brand with multiple products I have a chance to actually build a community off Amazon and brand loyalty. BUT that might mean choosing products to stock in my branded store that are VERY high competition products. For example if I’m in pet niche and make a pet brand, maybe I have one winner pet product but my next products I add to the store might not be as easy to rank for and sell through and could be very low profit/percentage of sales.

If I do the portfolio of random products strategy instead, I can focus on only products with highest chance of success. Even if they are completely unrelated.

Which do you think is better today and which method do you use?