The is no evidence that marijuana use will influence muscle growth is a positive way. The best thing for muscle growth and recovery is good ol' fashion sleep.
If you personally need it to relax than by all means continue but until there is any supporting evidence don't assume it will help reach a "relaxed muscle growth" state. Marijuana does induce "deep" sleep in certain individuals so this could be considered a major benefit.
Yes, Marijuana use will reduce T levels but only temporarily but so will sugar, certain foods and/or fats. Even certain exercises, like cardio, reduces T levels in certain age groups. It is simply a balancing act.
Rest assured that you will not screw up your body’s ability to build muscle if you choose to use marijuana. The rest is up to the individual.
FYI- I am not a user just an over educated gym rat!
SEMPER FI