fyi, yes, samsung monoculture is very strong. No foreign phone brands, especially Chinese, have gained significant market share (except apple ofc). Samsung with their 70% market share has been the undisputed champion in S. Korea for probably the whole post-iPhone era, even in the budget segment. Romming community does exist here and quite vibrant for its size but Samsung pumping out literal truckload of phone models (not to mention their carrier-locked variants which are more common like in the US), Knox (ew) and general public sentiment against modifying their devices means it's not really visible.

Thank you for these comments!

It's great to hear that the compatibility situation isn't that bad in Korea. Have you considered submitting the apps to https://privsec.dev/posts/android/banking-applications-compa...? Otherwise people might make the same mistake as me (look at the list and assume it's impossible to use an alternate OS)