Does it matter which ROM I use to get OTAs?

So my S7E came with a branded rom from my carrier, update dated back in March when I purchased the phone and that's the only rom available to date and I never got any OTAs from Samsung.

So I thought it was due being a branded rom and I decided to switch over to an unbranded rom, ok, this time there were many updates after I flashed the rom available at sammobile but still haven't received any OTA, still stuck at G935FXXU1APER, 1 June Security Patch.

What's the deal with it? Do I have to keep updating manually? I was hoping for a better battery life that was announced back on some updates. On the other hand I'm missing some features from the branded rom that came with the phone such as the spam filter.

Last time I had a Samsung device was my S3 and it only updated from 4.2 to 4.3, on the other hand I kept getting incremental updates on my Sony devices through OTA.

I have disabled a bunch of system apps but I don't think they affect it, such as facebook, whatsapp and instagram, call me anti social if you must lol.

Thanks!

Edit: My device status is official, it's neither unlocked or modified in anyway.