Please refer to the main article linked above.
I see a lot of them showing "generic" approval for the GOP much higher than the Democrats, as well as approval for congress (run by the Dems) at historic lows.
That is true, but analyses by pollsters like Charlie Cook and Larry Sabato is indicating that even with that high approval differential in favor of us, the competitive seats in the House restrict us to a maximum of somewhere between 20-35 seats net gain, falling just short of winning back the House. Same for the Senate - most see us winning 5-7 seats, just short of majority. The columnists above largely say the same thing. Bottom line - even the most optimistic pro-Republican poll watchers are not predicting us winning back the House or the Senate.
Charlie Cook and Sabato are Democratic shills whose job is to spin numbers for their party.