I’ve been dealing with sciatica for a few months

So I’m not new in the fitness world, I’ve been training for several years but around a year ago I started to pay for a personal trainer to improve my workouts but it was worse cause I got injured and diagnosed with sciatica (he never corrected my posture). I never suffered any injury when I was training by myself and I got injured with a personal trainer 🤡 however, I tried to get back to my normal routine but the leg day has became difficult. I’m scared to add more weight because my low back will hurt, my friend suggested me change the squat for the hack squat machine and that I should avoid deadlifts but I don’t know, any recommendations will be appreciated!