In case you missed it, you can make the entire text of your public Mastodon posts searchable by other people by opting into the "full text search" system. This means all the words in your public posts would be searchable, not just the hashtags.
Instructions for opting into full text search are at:
@FediTips можно сделать весь текст ваших публикаций в #MastoDon (а не только хэштеги) доступным для поиска, выбрав систему «полнотекстового поиска» (из соображений конфиденциальности эта функция отключена по умолчанию).
As far as I know you can still opt in even if your server doesn't offer full text search. Your posts should be picked up by full text search on other servers.