Few Questions about updating

Hello good people of Asgard! Err… I mean Reddit! Good people of Reddit!

I got few questions that stuck in my mind after installing Ventura on my Mac Mini 2014 through OCLP. 1. How to update MacOS to newer version of it? For example: a) From Ventura 13.5.1 to 13.6.1? Can I use just OTA update from system settings or I need to download full system again(around 11-12GB) and fully install it again? Or maybe there is some way to update via OCLP? If yes, how to do it?

b) From Ventura to Sonoma? Also, do I need full clean install or there is some way to download stuff „as update”?

1. Is there any way to save downloaded part of „ISO” of MacOS when your download stuck? For example I got error few times when downloading Ventura and had to start from the beginning to download. I use limited data so it’s kinda waste when you have 8GB from 12GB, download fails(or my internet) and has to start from the beginning wasting transfer.