Will I be sinful for not being able to uphold ties of kinship except with my parents, especially since they may visit relatives without my knowledge, and I cannot go alone?

There is no sin upon you for the infrequent visits to your relatives due to your inability, and you are not considered a severer of kinship ties thereby. For maintaining kinship ties is not limited to visiting; rather, it is achieved through everything that is conventionally considered a connection, such as calling, messaging, and greeting. Maintaining ties has degrees, the lowest of which is refraining from abandonment and greeting. It varies according to ability and need, with some aspects being obligatory and others desirable. Whoever fulfills some form of connection is not considered a severer of ties, even if they fall short of its ultimate extent.