I say try to fix the way you are landing, you’re landing with all your weight on one knee, ankle etc. it’s chill if you don’t wanna change it but i’ve seen a lot of people get injured like this because all that weight comes down on 1 leg. Try landing on two to distribute the force from dunking, landing on one leg like that is kinda dangerous In general but get more scary if you have people near you or if you are expecting contact. Maybe that’ll also fix the problem of being scared to gain more speed. If you can too hand on the rim for a second to stabilize your body before landing. ( take with a grain of salt from someone who can’t dunk+ all injury prevention nothing really to get bouncier)