Meeting them in the US, UK, and Canada, every single Sylheti always tries to convince me that they are different to Bangalis and closer to Pakistanis.
They are most of the ones who attend masajid, go on tableegh, and keep long beards. There are some Bangladeshis also who do that, but mostly they have a secular outlook.
I noticed that all Sylhetis prefer the company of Muslims, like Pakistanis and Arabs, and don’t feel shy about it while there is a significant group (not all) of Bangalis who prefer the company of Indian Hindus (even having no problem dating Hindu males/females) and become timid and self-conscious around other Muslims.
The Sylhetis also generally tend to support Pakistan/Kashmir and other Muslim countries and see their origin in Turkic, Persian, Pukhtoon groups.
Most Bangladeshis in the West of the recent new immigrant generation have a lot of anger and resentment towards Pakistanis, but the earlier immigrants from Bangladesh (80s/90s) and Sylhetis don’t have those negative feelings generally.