I like to build Monogram kits, the same ones I built as a kid in the Seventies. The 1/48 scale kits are still pretty good models (sorry, Hyperscalers!), and can be good simple builds, just for enjoyment. My favorites among those are the P-51B and P-40B kits, the P-39, the P-47 (razorback and bubbletop), the Typhoon, and the TBD.
I also like Monogram's old original US Navy planes, though I concede that they're still closer to toys than scale models. But again-they can be built for enjoyment. And even with the operating features, when you're finished, you have a good representation of the subject.
I've got some old pre-merger Monogram and Revell kits in the stash, too, that I never built back then, but which I've picked up, out of curiosity. Both companies made P-51Ds, for example, and both made Spitfires, albeit different marks. Revell also made a P-40E, scaled down from their 1/32 kit. That kit was the basis for the ProModeler P-40E kit, by the way. I never built any of those, but I'm building them now, in my 50s.
I also like Monogram's large 1/48 multiengined aircraft kits-the B-17G, the B-24D and -J, the B-29, and the B-25 kits. Again, today's modeler might turn up his nose at those, but if you're getting back into building, those are good kits to work with.
I'll also recommend Tamiya's P-51B and F2A Buffalo. Tamiya kits are good, generally, for their engineering and fit, and for the look of the finished model. You can't really go wrong with those.
Airfix has good 1/48 scale kits, too. Airfix has been issuing new-tool versions of subjects they produced years ago, and they are also worth picking up. Not over-engineered, not tricky for someone getting back into the hobby, and build into nice models.
Eduard has good kits, too, for the same reasons. I like their P-39 series, particularly.
Hope that helps!