First let me say that the way I do things is not necessarily the way everyone else does them. For example, some people think posts are the spawn of the devil and so build all their WordPress sites using only pages. I think this stems from a belief that posts and pages are fundamentally different from one another, in a bad way.
In Oxygen, each time you add a new page or post to your site, you must also decide how that post or page will be created. You will always have two choices.
As I explained elsewhere, I think it's best to put your content inside posts.
I do this by creating post content in Gutenberg but I deliberately only use the simplest Gutenberg blocks. I will use Gutenberg blocks for headings, paragraphs, images, quotes and videos. That's about it. I'm not interested in any third party block libraries or any complex blocks. I might use the occasional column or table. But in general I like to keep it extremely simple. The rules of thumb I mostly apply are :
The purpose of this content is to educate and to help my audience, and to rank in search engines for terms I hope my audience are typing. This content is there to build traffic.
The Gutenberg content will then be sucked out into an Oxygen template - which will effectively frame the content.
For posts, I like to use Option 1 above.
I use pages to build standard web pages like About, Terms, Contact, Privacy etc, and also to build Landing Pages. Landing pages are the home page, and any page where you might be directing people to go to take some sort of action. The action might be, for example, to sign up to something, to buy something or to download something.
Landing pages do not tend to do very well if they are not bursting with arrows or other pointed attempts to direct the user's eye. On landing pages use catchy and noticeable headings to get people to do what you want them to do. Landing pages are almost the opposite content pages. They are not there to ranke for anything, they are there to convert.
To this end, using standard headings like the ones that are used on the informational blog posts, or the same sized text - as used on all the content pages - may not be suitable. You'll need to keep within your design regarding use of colour, but you can also go a little off-piste to make the landing pages more noticeable to the human eye, and therefore more likely to convert. Landing pages need to look like you put some effort into them.
So for this type of page I often don't simply siphon the content out of Gutenberg into an Oxygen template. For landers I will do the content and the design in Oxygen. Why? Because it is easy to make fancy, eye-catching pages in Oxygen.
For landing pages I like to use Option 2 above. But for standard pages such as About, Terms, Privacy etc., I use Option 1 above.