How to repent from a sin i committed long ago

Assalamu alaikum wa rahmatullahi wa barakatuhu, My question(s) requires an explanation of my situation. I apologize for not being able to put it in simpler words, ...... before i reached puberty i stole from my classmates and back then i justified myself like so: ("They were spreading lies about me throughout the classes claiming that I have insects -Pheidole ants- in my hair and that this contagious disease can infect them; when my hair was perfectly fine *aside from this they spread other lies about me and got a lot of people to avoid me* so it is fine if i do this to them because they have hurt me first _ thought my younger self" i know this is not fit to be a justification and knew it was not back then too but denied it like that), throughout the year i had moments where i would be overwhelmed by guilt and so i would return the stolen objects back to their owners in secret and without asking for that person`s forgiveness (now i know that i can never be forgiven if the person i harmed does not forgive me himself and i know how they will be getting back their right on the day of judgement) the problem is:- 1. i lost some of the things i stole and these objects never returned to their owners 2. as i mentioned before even if i returned most of the items i stole out of guilt back then .. i still never apologized for my actions and sadly now i can not even do that because i do not know where they are 3. Out of all the things i stole i have either lost or given back the items except for Only two objects from all these stolen belongings that are still in my possession until this very day, i do not know what to do with them because i have lost all contacts with their owners and a really long time has passed since then. Alhamdu llallah i never stole anything from anyone the moment i actually hit puberty though. Now that i have explained the situation, i would like to ask what to do with the 2 items that i still have in my possession? how do i repent? i know that allah subhanahu wa ta'ala is the all merciful and will surely and in shaa allah forgive his servants when they seek his forgiveness, but what about all the people i did not apologize to back then (all of which i have lost contact with)? is there really nothing i can do to avoid what will happen to me on the day of judgement if i can not find the people i stole from back then and ask for their forgiveness now? Please help me out