Advice needed on URL structure change (first time doing it, don't want to mess things up)

Hello,

I'm a little bit scared with my first ever URL structure change.

My 6 months old website has already a bad URL structure and I don't want to regret not changing it now when it still has low traffic and not many BL.

Current structure

{www.domain.name}/blog-post/{article-name}

Problem with this structure : 1/ "blog-post" is too long and 2/ I would prefer a topic-dependent structure instead of generic term like "blog".

Target structure

My target structure would be topic oriented, with the topic at the root :

{www.domain.name}/{topic} => topical hub

{www.domain.name}/{topic}/{subtopic}

Two issues I see, but there could be others that I don't even know exist :

1/ Some of my current pages already have external BL, from some high DA sites. I understood that I needed to do some redirect from old structure to new structure with 301 redirect. However, I don't quite get if this will impact the juice flow negatively? Is there a better way apart from asking the website to change the URL in their articles?

2/ I am hosting my website on webflow. Currently, I have one dynamic template linked to the URL /blog-post/{article-name}. With the new structure, will I have to create a new dynamic template for each of the topics in my URL even if the content structure is the same? That seems to be a lot more work than the current simple setup...

And to finish, the most important question, would you advice for this URL change, and do you think it would have an impact on my ranking? If so, will it be marginal?

Thanks a lot for your help!