Some of the game catalogs are extensive. The largest is the MS-DOS catalog with several thousand entries. Not sure why it’s so slow to edit the catalogs. All of the lists of games are in bullet lists so that two columns can be displayed.
Gutenberg does have columns available which is an option but the style in use comes from the old HTML era. While it is possible to convert to paragraphs, the spacing becomes wider and the length of the document becomes even worse.
Hyperlinks in the catalogs point to known game reviews. There are several catalogs from MS-DOS, Xbox etc which are all enumerated. The goal is to be able to identify those games more easily by platform as many games reviewed are multiplatform. The categories handle the various platforms and genre etc.
Chrome and Edge are both 64-bit and the machine has 32GB of RAM to load any document easily. So why the slow edit seems to be related to the sandbox which is designed to protect a machine from malicious websites. The CPU has several features that are supposed to be able to keep malicious apps away.
There is always using Expression Web 4 to handle the catalogs and paste new versions into WordPress which is one way to solve the tedium of hyperlinking game lists.