What are the best exercises to do at home to strengthen low back and core in case of sacralization L5 to alleviate symptoms. Thanks?

Lot you can do .. Quite a few exercises could be nominated. The exact exercise is less important; doing them 3-4 times a week is key. Do each for 8-10 reps, working up to 3 sets. 1) Seated bent over stretch: sit on chair, bend over shoulders moving between knees, lower if possible. Hold 20 seconds. 2) Bridge: Lie on back on carpet/mat. Bend knees, raise hips until knees/shoulders in line. Hold 2 secs. 3) Quadraped: begin on all 4's. Lift arm/opposite leg, slowly lower, do opposite. 4) Superman: Lie on stomach, raise arms/legs/chest. Hold 2 sec. Good luck!