There's a website named imginn which serves basically the same purpose as Bibliogram but unfortunately they are closed source, they somehow manage to bypass the 12 posts restriction Bibliogram is suffering from a long time.
I don't really know how they're doing this in the first place, probably multiple accounts like Aurora Store is doing for Google Play ? I imagine they may also need a pool of "user" IPs like not hosted by AWS or so ?
Shouldn't be possible to research or even maybe ask them (i know very unlikely but maybe we're in a good timeline) ?
I don't know how Instagram login works too or how aggressive are their anti-bot/scrapper protections but would it be simple to add a system using a one or a list of accounts to access resources unrestricted ?
Almost certainly uses fake accounts. Registering an account on Instagram requires agreeing to the terms of service, and the terms of service say that you can't scrape the site, so this will never be officially supported.
but would it be simple to add a system using a one or a list of accounts to access resources unrestricted ?
You can do this pretty easily by editing the source code of Bibliogram to supply relevant HTTP headers. No further support for using fake accounts will be provided.