What makes those models difficult to solve? Where can I read about such a model? It seems plausible that something would be computationally intractable; it seems less plausible that you couldn't do any modeling at all.
If you want to learn more, you are spoiled for choice. There are lots of places to look. Here’s a random list from the top of my head right now.
Ljungqvist and Sargent’s Recursive Macroeconomic Theory is a standard grad level text taught nearly everywhere. Has been for probably 20 years.
Stokey, Lucas and Prescott is another, more math methods focused.
DeJong and Dave is a macro empirics book.
Jianjun Miao’s book is another solid option.
Stachurski focuses on computational methods.
Acemoglu has a book on modern growth theory.
McCandless “the abcs of rbcs” is IMO underappreciated.
Beyond this you’ll need chapters from various volumes of the Handbook of Macro and related texts. There’s a long one by Fernandez-villaverde and co-authors about modern DSGE models. That’s available for free on his website I think.
It’s a huge literature. If you are serious about it, enjoy and good luck!