Global convert to uppercase and lowercase in macOS?

In Mail.app and Text.app there's Edit > Transformations:

• Make Upper Case
• Make Lower Case
• Capitalize

...but I see no keyboard shortcut options in:
System Preferences > Keyboard > Shortcuts:: Services.

Is there a way to get this functionality available globally for all text entry? For example, web based forums like Stack Exchange.

Of note, the options are available in Safari.app's Edit > Transformations menu:

...but not in Chrome.app:

I could change my browser habits, but it would be nice to know if there is a way to add this functionality to all "Edit" menus.

You can do it in Safari, but Chrome ignores the standard Mac Toolbox, unfortunately.

System Prefs > Keyboard > Shortcuts > App Shortcuts

You can set key commands for All Applications, which will then work for all that have the requisite menu option.

This is my own setup, which shows keys already set for Capitalise & Lower Case
I use it a lot for such as Stack Exchange.

This free app has worked on all Mac versions for over a decade and is still current for Catalina 10.15:

WordService

WordService provides a large number of commands for working with selected text. Extend your favorite word processor, email app, or web browser e.g. with functions for reformatting text paragraphs, cleaning up tabs, quotes, or line endings. Remove unwanted text parts, sort lines or paragraphs, change case, and do much, much more with text.

• https://apps.apple.com/us/app/wordservice/id899972312?mt=12
• https://www.devontechnologies.com/apps/freeware

You can install a macOS service called "Wordservice" that works great on paper, howeverI have found it to be buggy, working / not working, requiring resetting, and generally not being reliable.

But when it works it's great, and system wide. Still trying to find a better alternative though.