Simple category & tag management tool for hobby WP

Hi!

I have a small personal “blog”. It’s truly just for me, mainly used to store links to articles of interest to me, sometimes with my own thoughts added in the comments. Simple WordPress 5.4.2 install, PrimeWP theme. Just a few plugins, with Press It! being the only one that I use.

Knowing nothing about “taxonomies”, I didn’t bother thinking about how to best structure things. Turns out I used categories too much and tags too little. I now need to make some changes to both “Categories” and “Tags”. Mostly convert all the “Categories” to “Tags”. Then I can prune down the “Categories”.

I’m sure this can be done with a few quick SQL statements, but that is beyond me. I can follow tutorials if such exists. I have full access to my databases, can & do make regular backups, etc. I was a pretty good BASIC & Pascal programmer back when that was relevant, just never dealt with SQL.

I did find this plugin: https://wpsheeteditor.com/extensions/categories-tags-product-attributes-taxonomies-spreadsheet/?utm_source=wp.org&utm_medium=web&utm_campaign=taxonomy-terms-lite-buy

and it looks like it would do what I want, but I really need a free, or perhaps a one-time $5 fee. My SO already looks sideways at my yearly hosting fees for my “blog” thingy.

Anyone know a plugin that would suffice. Or a gentle explainer on the necessary SQL spells required?

Thanks for listening!