Read "The Long Road To Segwit: How Bitcoin's Biggest Protocol Upgrade Became A Reality" by Aaron Van Wirdum. He's definitely the most trustworthy person you can find that wrote about the subject-matter.

https://bitcoinmagazine.com/technical/the-long-road-to-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality

That write up will give you the history, what caused the "Scaling Debate", the context why, and why the the Core Developers chose the path where we are today.

It is interesting that almost everyone remembers the "block size war" as the end of it in 2017 and with the shitcoin called bcash. In truth this "conflict" about scaling bitcoin lasted at least 5 years and it definitely wasn't just bcash versus bitcoin with only 2 sides. There were many sides or better said many different proposals for different approaches which we may categorize in a simple way into 2 or 3 categories.

1. The group saying bitcoin should scale using the second layer and should not have a hard fork.
2. The group saying bitcoin should only scale on-chain (layer one and only layer one) by hard forking to a bigger block size
3. The group saying both at the same time. This was short lived and was very messy mainly seen in SegWit2x which had its own separate issues.

Of course this is an oversimplification since for example the second group consists of many different approaches like one saying we should have a one time fork to a massive block size while another saying we should let the miners choose to change the size at any time they wanted, etc.