Based on our record, Google Input Tools seems to be more popular. It has been mentiond 4 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I used Google Input Tools a lot on Chrome to transliterate/type in multiple languages very easily through my browser, but it's not available on Firefox. If it helps, I am also using Linux in case there are any tools on that end which make a Firefox extension unnecessary. Source: about 2 years ago
I do something similar as well. I have https://chrome.google.com/webstore/detail/google-input-tools/mclkkofklkfljcocdinagocijmpgbhab installed in Chrome and have a hot key to switch between scripts. Source: over 2 years ago
There's a Chrome extension that allows you to type those diacritics, but that's the only input method I know that supports them. Source: over 2 years ago
If you're chrome user, you can try chrome extension Google Input Tools . Source: almost 3 years ago
Google Japanese Input - A Japanese input method editor.
Unistroke Keyboard - Unistroke Handwriting Input Method for Programming