I spent at least 2 hours investigating this and found no practical solution. Of course there ARE ways to do it, but they are inconvenient, and you cannot type fast while doing it. None of the standard European ways of getting accent work with Cyrillic, and the Cyrillic keyboard itself doesn't have any accessible key for accents that I can spot. The universal code for accent don't work on cyrillic letters. I have resigned to using Bold, Underlined or a different colour to indicate where the stress is.

Not sure how sites like Wiktionary achieve this (below) Maybe they are using a third party plugin. Perhaps someone could check their editor facilities.

бу́ду плати́ть
бу́дем плати́ть
бу́дешь плати́ть
бу́дете плати́ть
бу́дет плати́ть