Go lingojam.com and start creating a language. Source: about 1 year ago

I don't think there is a way to make custom IME yet, so the only way I know of is sites like https://lingojam.com that allow "translating". Iconic uses it for text<->emoji so it's not just for ciphers. Source: over 1 year ago

For anybody interested there is this website which allows you to create a translator for any fictional language of your choice. This slime language created by GPT could fit really well in there. Source: over 1 year ago

It's updated frequently, as is the link. You can probably just find the latest version of it if you just go to lingojam.com and select 'browse more translators". Source: over 1 year ago

At the end it kind of sounds like lingojam.com but idk for sure. Source: almost 2 years ago

Check this site, has a lot of themes to choose from (and install using plugin) https://rainglow.io/. Source: almost 3 years ago

Looks like they have themes for other editors too. Source: about 3 years ago