Cannot make an espresso (ariete 1389)

Hey guys, in the last time it seems like my ratio is really off; like 1:~3.7/4. I’m using currently ground coffee and really soon moving to grinding beans daily. The machine I got is really an entry-level machine mainly for people who “want coffee” yet don’t know anything about making coffee. I tried 18gr and 16gr, pulling water around 30sec, sometimes more sometimes less and aiming for 36-40gr for the 18gr dose and 32-36gr for the 16gr dose. It comes out sometimes acidic sometimes good/bitter and mostly really disgusting. I use wdt and leveler yet not temping because in my experience with the machine the water just can’t pass the coffee. I think I missed something about the process. Any help is accepted, thanks guys a lot.