It honestly makes no sense to me. The time jumps are giving me whiplash and this first season could have explored things in much more detail like you said. I like the show but it’s a weird narrative choice to go so fast when that was the major complaint about how GOT ended.
What people don't seem to get is that everything you're seeing on screen right now was all going to be backstory when this show was pitched the first two times to HBO.
All of this comes from interviews and articles that have been put out by EW, Variety, and podcasts.
The first two writers (Carly Wray and then Bryan Cogman) that GRRM worked with on a Dance of the Dragons prequel pitch both wanted to start the series at the Dance. If that would have happened, literally everything you're seeing on screen right now would would have been shyt the characters would recount in exposition dumps.
"Remember when we fought in the Stepstones."
"Remember that time Rhaenyra married Laenor and Alicent wore Green and upstaged her."
"Remember that time Rhaenyra was made heir after her mom died in childbirth and Daemon made an heir for a day joke."
That was going to be the approach. There wasn't going to be a young Rhaenyra or young Alicent. There was only going to be the Dance.
Condal was the first and only writer that came to this project (well, he was handpicked by GRRM after the first two writers didn't pan out) and was willing to explore the period before the Dance because he was the only one willing to do the risky and difficult business of casting lead actors twice for the same character and committing to time jumps. Everyone else thought telling that many years worth of story, and going through multiple actors for characters would be a non-starter for a tv show adaptation.
And even then, Condal going into the project with the idea to start well before the other showrunners were going to start was a compromise with GRRM and HBO that would still allow the first season to get to the thing that sells the show. HBO was not going to greenlight a Dance of the Dragons show that doesn't feature the Dance of the Dragons.
So the options for this show was always either going to be enjoy as much of the pre-dance as you can with timeskips, which is what we are getting with House of the Dragon, or have the very first episode basically be the start of the Dance. There was never going to be multiple seasons of pre-dance only material.