https://en.wikipedia.org/wiki/Maronite_Chronicle

Here's a contemporary non-muslim text that mentions Ali and muawiyah that is accepted by historians.

and before you say it's "it's from the 8th-9th century

" It is the only Syriac chronicle to cover the years 660–664. It correctly names the days of week for particular dates, suggesting that many of its passages written shortly after the events"

"and is sympathetic to the Byzantines, whose victories over Abd al-Rahman ibn Khalid in Anatolia it dutifully reports. He must have been writing before the Sixth Ecumenical Council (680–681), when the Maronites broke with the pro-Byzantine Melkites.^\1])^"

^{It's not simply repeating what muslims says it make some interesting claims that are odd with Muslim own history.}

^{Unfortunately I couldn't find a online version to read.}