If I join some brothers to read quran and that I do it to get rewarded by Allah, but sometimes also to keep our bond, and hear about them, or even to not feel alone, or by fear that some brothers feel resentment towards me because I don't connect with them often Is there shirk in my intention?

No, this is not shirk, and you get rewarded for this. Your intention is that you want to protect yourself and your religion from other things. You want to bring happiness to your fellow brothers, and to sit in the sittings of the Qur'an, studying the Qur'an and revising it. Therefore, you get rewarded for this. BarakAllahu feek.