These hadith are considered authentic by many Muslim scholars :
Hadith 1663
Narrated Al-Miqdam bin Ma'diykarib:
That the Messenger of Allah ﷺ said: "There are six things with Allah for the martyr. He is forgiven with the first flow of blood (he suffers), he is shown his place in Paradise, he is protected from punishment in the grave, secured from the greatest terror, the crown of dignity is placed upon his head - and its gems are better than the world and what is in it - he is married to seventy two wives along Al-Huril-'Ayn of Paradise, and he may intercede for seventy of his close relatives."
[Abu 'Eisa said:] This Hadith is Hasan Sahih.
https://muflihun.com/tirmidhi/22/1663
Hadith 17117
The mention of 70 or more Hoors for the Shaheed is reported by several Sahaaba (Radhiallaahu Anhum), of them are:
1. Sayyiduna Miqdaad ibn Ma?adikarib (Radhiallaahu Anhu) recorded by Imaam Tirmidhi in his Sunan (Hadith1663). Imam Tirmidhi has classified this Hadith as Sahih (authentic).
2. Sayyiduna Ubaadah ibn Thaabit (Radhiallaahu Anhu) recorded by Imaam Ahmad in his Musnad (Hadith17117), Imaam Bazzaar in hi Musnad and Imaam Tabrani in his al-Majmu?al Kabir. (Majma-uz-zawaaid vol.5 pg.293). Hafiz Munzhiri (ra) has classified the chain of narrators of Musnad Ahmad as Hasan (sound). (al-Targheeb vol.2 pg.320). And Haafiz al-Haythami (ra) has mentioned that the narrators of Musnad Ahmad and Tabrani are all reliable.
and Allah Ta’ala Knows Best