My experiences learning Japanese (日本語) and traveling to Japan (日本).

Generally I will write Hiragana for every word, but I will not write any romaji. You should take the time to learn the Hiragana. I would recommend Duolingo for learning that. After that it gets a bit tedious, and the core lessons for Duolingo can be too easy, especially on mobile where switching off the word bank isn’t possible.

LingoDeer is a pretty useful, but unfortunately not free tool for learning Japanese. I would not recommend it for languages that use the Latin alphabet. I tried it with German and it is not challenging enough to make the words stick in your brain, but you can still use it to get an overview of vocabulary.