Hi, there.
Sometime and some time is the exact same thing. It has two forms, adv. and/or adj.
A. adv. (at a not known, not specified or not decided time): We saw each other sometime last week. He will arrive sometime next month.
B1. adj. (Only before nouns) used to refer to what sb used to be: Mark Jacobs, sometime doctor at this hospital.
B2. In American English (AmE) user to refer to what a person does occasionally: I am a sometime freelancer for this news agency.
SOMETIMES is and adv. and refers to an occasional rather than frequent activity: He sometimes visits on Fridays. Sometimes I prefer to stay at home. She sometimes sings when we go out. Sometimes it is difficult to understand his way of thinking.
Cheers,
Lida