Is there anything I can do to have these limits increased?
To increase the limit you have to rank up to legendary (2 seconds)
According to this
post the smallest limit to actions (such as posts and reports) is 4 seconds.
4 seconds isn't long to wait IMO, and I guess that's enough to prevent spamming the server to post submission of reports unless there's a way to increase it to 3-2 sec.
I was trying to report many posts at ~once, and 4 seconds was too long for me. If I were to build a bot to report posts, 4 seconds would be well below how quickly a bot could identify spam posts.