Problem of frequent spam comments from same spam commenter(s)

Some spam comments on this blog are unavoidable. But the problem is that some spam commenters keep commenting even when their earlier comments are marked as spam and so do not show in the associated blog posts. I googled for a way to block some such spam commenters. Looks like Blogger does not have an in-built mechanism for that. I can stop all comments or limit comments to those with some id (like Google id) but I don't want to do that as that might block some genuine commenter. Further, the regular spam commeters also seem to have Ids like Google/Blogger id.

This article claims to give some solution which involves inserting jquery code in blogger theme: How to Ban Someone Commenting on Your BlogSpot Blog, https://www.knigulper.com/2017/11/ban-spam-user-commenting-on-blogger-blogs.html . As of now,  I don't want to get into inserting such code into the blogger theme(s) I use. But I may try it out in future, if required.