My personal suggestion: First of all, send an e-mail to the customer support, and then find out if anyone has blocked any of your photos for being an adult photo or offensive. Thirdly, if the previous step failed, try using another device or computer if you have a malware or block in your browser. The fourth step you must take is to delete your account after you have backed up your photos and try to create a new one where you upload both new and old photos.
The only reason why Instagram may want to block your comments is when they believe your comments violate any of their terms and conditions.
I once encountered a similar problem and had to change the information on my profile page without any delays.
Try and get rid of your entire bio to see if you will be able to post your comments. If you post the comments successfully, you can then rewrite your bio and adjust the content/wording.
I hope the above tips have been able to help you learn how to comment on Instagram posts without getting responses that say your post has been blocked.