Well congratulations on passing your Tech and General tests. The number of questions that you got right or wrong, makes no difference. What matters is that you passed. They only record pass/fail. And lucky guesses still count. And, even if you failed, you can go back and try again. Sometimes they will let you try again, at the same test session.
The only thing your losing, by not passing the Extra, is some band space. So if you are operating somewhere on the HF bands, be careful of your frequency. Lots of new guys wander into the Extra band space without realizing it. And, no, just because the Advanced ticket is no longer offered, you can not use the Advanced band allocations. However, when you finally pass the Extra test, you gain the Advanced and Extra band space. This
ARRL Band Chart should help you keep on track.
I got my Novice license in 1965, when I was in high school, but I didn't bother upgraded to Extra until 1999. I took the Tech and General at one VE session and then I took the Advanced and Extra written tests about 2 months later. Again, at a single VE session. All I did was read through the entire question pool, so that I was familiar with everything, and then took a few practice tests. (
QRZ.com has practice tests for free). I didn't memorize the questions. If I couldn't guess the correct answer, I just looked it up to find out why. Some of the questions were pretty tricky. Of course, I also had to take the 13 and 20 WPM Morse tests, but that is none of your concern any more.