I don't read any novels that are the originators of manwha/manhua/manga and this actually isn't the much of a slow burn at all. In the romance depending, sure, it's a tad slow, but plotwise, not at all. If you read regular novels, this is on par with pacing, timing and arcs. Most webtoons now are 3-4 seasons with a month or two gap in between so that those working on it can recoup and deal with medical issues that crop up mid season. If you don't like the development pace, I would stay away from anything that is set in fantasy realm like this because they all have political power-struggle plots that are paced this way. If you're looking for straight smut, you're going to run into a LOT of rape storylines. You need to find stories solely focused on the romance aspect or you're going to end up with what you subjectively consider to be an exceedingly slow-burn. But whereas stories with pacing like this have shorter wait time between seasons, those strictly based on romance who have committed to 2-3, sometimes 4 seasons, have far longer gaps between. I have a couple of lists in my page you can check out with a few faster paced ones that are completed if you want to check them out. BJ Alex might be a good start for you if you haven't read it.
I get that this is a long ass story with hundreds of novel chapters, but I think the pace is not suited for a manhwa. The art is great, the characters are nice and with proper development, I can see myself loving a lot of them.
My issue is that the novel to manhwa conversion should be adjusted. For example, some manga stories are converted to anime in a "1 chapter = 1 episode" and it works, in other cases, it's "3-4 chapters = 1 episode" and it works the best for that story. The issue I have with this manhwa is that it feels like there should be more material per chapter. Season 1 solely introduced characters with almost 0 progress or development.
Maybe novel readers are loving this because it covers a lot of the source material. But as someone who is only reading the manhwa, this is slow as hell. It would've been slow anyway but considering that we will have to wait 3-5 months in between seasons, is this meant to be a 10 year long adaptation?