My dear Maharaja,
Narasimha prayers are recited by devotees everyday which explain the meaning of "vasudeva sarvam". Here is the meaning:
"Narsimha is here. Narsimha is there. Wherever I see, there is Narsimha. Narsimha is outside and Narsimha is in the heart. I take shelter of that Narasimha who has no beginning i.e beyond matter which has beginning."
The self has assumed false affinity with the matter. The true affinity of self is with Krishna. Everyone is part of Krishna. We are Krishna's and only Krishna is ours. This world is not ours but belongs to Krishna. We are supposed to use the objects of this world which belong to Krishna in service of living entities which are manifestation of Krishna.
I think when we accept the above statements, then all doubts, problems etc are resolved. You will find the discussions on guru tattva meaningless or even stupid after accepting above statements. Most people start preaching without accepting or even understanding above statements. That is quite sad as their preaching deviates us from above truths.
HpS - Jaya Hare Krsna. Srila Prabhupada Ki Jai. Krsna says in Bhagavad Gita 5.29
Krsna says that He is the enjoyer of all sacrifices. So we can certainly agree that service to Jivas in an enlightened perspective is part of serving Krsna, but Guru and the Deity are also forms that Krsna authorizes to receive service. Otherwise we have the problem that we think that we can approach Rama, Krsna, directly and that Laksmana and Sita are not important. That was Dvidvida and Mainda's problem, no? They could appreciate that Rama was God, but they just thought that Laksmana was a person like them who had done a lot of austerities. Then in Krsna lila Dvidvida realized that Guru, Balarama, Laksmana, is just as powerful as God.
We hope you are getting enough rest yourself, as one of the manifestations of Krsna!!!!