Sambo, BJJ, and wrestling will all help each other. In my opinion, Sambo, Judo, BJJ, and wrestling are all just different facets of the same art, which is close-in grappling (as opposed to the arms-length grappling which arts like Aikido focus on). They have different competition rules, but the underlying principles and skills are mostly the same.
Likewise, I learned Muay Thai and boxing together. There are contextual differences based on the rules, but they can synergize well.
Do you actually have a school which offers all 5 of these arts? If so, youāre pretty lucky. In addition to the convenience of having all that instruction in one place, the teachers would likely understand how aspects of each art overlaps with or differs from the other arts. If youāre having to travel to different schools, I might not bother. Teachers at a school with only one art may not be as helpful in your integration of the systems.
In any case, if youāre wanting to compete in MMA, you should be training some place that has dedicated MMA instruction. Experienced coaches can show you the specific elements that are pulled from each art which are relevant for MMA and show you how those elements work together in that context.
Also, while Muay Thai, BJJ, wrestling, Sambo, and boxing are all excellent foundations for MMA, it is absolutely not true that you need to train in all 5 of those to be successful in MMA. What you need for MMA (skill-wise) is competency in striking, clinching, takedowns & takedown defense, and submissions. You can gain those competencies through a variety of arts, including pure MMA classes. (Although I recommend studying at least one or two of the more specialized arts, such as BJJ or boxing, in order to gain a more in-depth understanding of those aspects.)