Assalam O Alaikum WaRahmatullahi WaBarakatuhu,
I will quote two Hadiths to answer your questions:
Nu'man b. Bashir reported that the Messenger of Allah (ﷺ) used to recite on two 'Ids and in Friday prayer:
" Glorify The name of Thy Lord, the Most High" (Surah lxxxvii.), and:" Has there come to thee the news of the overwhelming event" (lxxxviii.). And when the 'Id and Jumu'a combined on a day he recited these two (surah) in both the prayers.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَأَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَإِسْحَاقُ جَمِيعًا عَنْ جَرِيرٍ، - قَالَ يَحْيَى أَخْبَرَنَا جَرِيرٌ، - عَنْ إِبْرَاهِيمَ بْنِ مُحَمَّدِ بْنِ الْمُنْتَشِرِ، عَنْ أَبِيهِ، عَنْ حَبِيبِ بْنِ، سَالِمٍ مَوْلَى النُّعْمَانِ بْنِ بَشِيرٍ عَنِ النُّعْمَانِ بْنِ بَشِيرٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقْرَأُ فِي الْعِيدَيْنِ وَفِي الْجُمُعَةِ بِـ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى} وَ { هَلْ أَتَاكَ حَدِيثُ الْغَاشِيَةِ} قَالَ وَإِذَا اجْتَمَعَ الْعِيدُ وَالْجُمُعَةُ فِي يَوْمٍ وَاحِدٍ يَقْرَأُ بِهِمَا أَيْضًا فِي الصَّلاَتَيْنِ.
Reference : Sahih Muslim 878 a
In-book reference : Book 7, Hadith 78
USC-MSA web (English) reference : Book 4, Hadith 1907
From this Hadith we can conclude two things:
- One can recite Surah next to each other in Salah. As we can see Prophet (peace be upon him) Used to recite Surah 87 in first Rakah and Surah 88 in second Rakah in Friday prayer.
- Surah 88 is slightly bigger than Surah 87 and yet prophet peace be upon him recited a longer Surah in second Rakah. The following Hadith shows another example according to which prophet peace be upon him used to recite Surah 32 in first Rakah of Fajr on Friday and Surah 76 in the second Rakah. Surah 32 is almost 3 pages long while Surah 76 is one and a half page.
Ibn Abbas reported:
The Apostle of Allah (ﷺ) used to recite in the morning prayer on Friday Surah" Alif-Lam-Mim, Tanz'il ul-Sajda" (Surah xxxii.): Surely there came over the man a time" (Surah lxxvii) and he used to recite in Jumu'a prayer Surahs Jumu'a and al-Munafiqin.
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدَةُ بْنُ سُلَيْمَانَ، عَنْ سُفْيَانَ، عَنْ مُخَوَّلِ، بْنِ رَاشِدٍ عَنْ مُسْلِمٍ الْبَطِينِ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَقْرَأُ فِي صَلاَةِ الْفَجْرِ يَوْمَ الْجُمُعَةِ { الم * تَنْزِيلُ} السَّجْدَةُ وَ { هَلْ أَتَى عَلَى الإِنْسَانِ حِينٌ مِنَ الدَّهْرِ} وَأَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَقْرَأُ فِي صَلاَةِ الْجُمُعَةِ سُورَةَ الْجُمُعَةِ وَالْمُنَافِقِينَ .
Reference : Sahih Muslim 879 a
In-book reference : Book 7, Hadith 81
USC-MSA web (English) reference : Book 4, Hadith 1910
With that said, scholars normally recommend to pray a longer Surah in first Rakah and a competitively smaller one the second Rakah because that was a normal habit of prophet ( peace be upon him). However, one can pray a longer Surah in second Rakah as shown in the hadiths above.
With regards to praying surahs next to each other, a clear practice of that can also be seen when one prays Taraweeh.
I hope you find this answer helpful. And Allah knows the best!
Ma’aSalaam
