How to 301 redirect removing a section of URL containing the word comment + random number

I recently moved my website to a new domain and changed a bunch of things. In the process, I seem to have ended up generating a lot of 404 errors due to URLs like this:

mywebsite.com/theblogpost/comment-68875

This occurs on a lot of blog posts, so the blog post bit is variable as is the number at the end.
I tried experimenting with a RedEx testing tool and a htaccess tester, but it would seem that I am not smart enough to work it out

I got about as far as \b(\wcomment-\w)\b which matched the phrase in RegEx testing but couldnt work out how to correctly apply that to a RewriteCond/RewriteRule

Thanks in advance for any help!

The question is a bit vague, but I think the important detail is how to match such incoming requests. You have to adjust the rest yourself ...

To redirect all such requests to the same target:

RewriteEngine on
RewriteRule ^/?[^/]+/comment-\d+/?$ / [R=301,END]

To redirect all such requests to the actual blog post:

RewriteEngine on
RewriteRule ^/?([^/]+)/comment-\d+/?$ /$1 [R=301,END]

I used absolute path here since the question reads as if you are using the DOCUMENT_ROOT folder as base. Obviously the rules can also be implemented using relative path.

I personally clearly advise to implement such rules in the central host configuration of your http server. You can instead use a distributed configuration file if you are using an apache http server and if you have enabled that featture beforehand (see documentation of the AllowOverride directive). But that adds complexity and really slows down the http server. So only do that if you have no access to the central configuration (read: if you are using a cheap hosting provider).