If you go to the all microblogs feed you can see all the microblogs federated to your instance. Alternatively you can use the combined feed and it will have both threads and microblogs mixed together however you may have to scroll a while or sort by new to see microblogs.
This is due to the difference in how users interact with the two forms of content and thus how they are ranked by the sorting algorithms. Threads will typically get more interaction with votes and comments than microblogs will because they are strutured more for discussion whereas with microblogs people tend to post more but each individual post gets less interaction and thus they get pushed down with the sorting methods used by lemmy/piefed/mbin.
Mastodon uses a chronological sort so if you do want to see more microblogs it would probably be easiest to copy that and sort by new. I'm starting to think the only way to get a good mix between the two types of post is to have custom client side algorithms but that can get kinda complicated so no one is really doing it.