TLDR; Is it OK or even normal to go for NSA sex and then build a relationship from there or is it frowned uppon?

This is new to me and I apologize up front for being a bit uncentered but i'm trying to find a way to ask a question that is still nebulous in my own mind. My wife and I within the last year decided to go open and like many men starting a life of ENM I have been having trouble finding dates. I've asked advice and gotten a great deal of it. Some seems to be of better quality than others.

Quite a bit of the advice i've gotten has been along the lines of work on yourself with vague hints that this means therapy, reading books, getting new hobbies. Vague enough that it is mostly not helpful. I've read many of the recomended books and have so many hobbies in addition to my full time job that I don't have time for any more. When/if i find a date i'll probably have to cancel something to make time for her. That is not what this post is about though.

Some of the the advice that was more specific was with regard to advertising, appear more interesting, don't ask for friendship beause everyone does that. Be clear about what you are looking for and take good pictures. This advice seems more actionable.

Whenever I get frustraited with searching for dates I delete all my dating apps and accounts and just focus on my daily workouts to get back in shape for a few weeks. When I have measurable progress I try again. I have yet to find any success but at least the actionable advice seems reasonable.

So now that i've gone over about 8 months of history and personal progress its time for my quesiton. When i'm advised to just be clear about what I want and don't ask for friendship is this how modern adult relationships begin? Is the proper sequence 1. check for sexual chemestry 2. decide if more than sex is possibble 3. spend time together to grow the relationship?

Is this the most common pattern? Is it an acceptable pattern? Am I failing to find dates because I want to spend time with someone doing something we both enjoy and get to know each other before we jump into bed? Would I be better off looking for NSA sex to begin with and if we get along more is possible up to and including poly relationships?

I'm also a bit off ballance because once we went open my wife had a steady BF who she is still with in no time at all. So there is that...

I have made a great deal of progress. I didnt start tracking my weight until feb but since then i've gone from 238lbs to 192lbs and i'm aiming for 150 to 155. I'm a short guy only 5'5" so 150 is Ideal. 190 is dad bod territory but no longer obese. It does mean I need all new pictures next time I actively start trying to date again... Confidence is a big problem for me.

Ok i'm rambeling and I've asked my question. I'll end this here.