If you're wondering why certain boosts get shown again and again, there is a feature built into Mastodon called "Group Boosts" which prevents you seeing the same boost twice. This is switched on automatically for everyone, you do not need to do anything to switch it on.
Unfortunately, it is also set to allow boosts to repeat after 40 other posts, and this number cannot be adjusted by users or admins.
If you're comfortable using github, vote for this to be fixed at https://github.com/mastodon/mastodon/issues/18693