losing streak against players who are too skilled compared to me

my uncle plays in a seperate room on a seperate computer on a seperate account but because of how the ranking and mmr system is because hes able to play and wreck diamond and plat players the system puts me against them even though im bronze and will never get better since i get teamed with silver and bronze players and against so many high skilled players so im seeing how many losses i can get while trying hard as i can. ima update how many losses i get after i finaly get a win but current count is 3 losses then 1 win everytime but the wins i obtain are by luck or enemy players giving pitty on us and lose on purpose