Mastodon is used by me alone and costs ¥1590/month.
Misskey is free with OCI for less than 5 people.
PieFed is ¥491/month.
Lemmy is the biggest server in Japan, but I host it at home because it has about 5 MAUs.
(Unfortunately, it is not popular in Japan.)
Media is R2, but it is still within the limits of no billing.
Arte Romaji Input (Japanese)
screen recording
https://files.korako.me/video/nyuryoku.mp4
Similar to Godan, but I prefer this one.