For social work there is zero relevance to pedigree of undergrad and where you get in.
My daughters Hillel director - her bio shows Salisbury undergrad and u of Michigan…#1 in this rank- for her msw. OP doesn’t likely have the credentials to be at a high pedigree school and frankly for even of their chosen future goals it’s unnecessary.
Op does need to find a school - perhaps a smaller one - where they can find motivation.
AFS offers a range of options depending on the countries. Some are half year or just the summer.
Americorps has great opportunities if 18 by the time the project would begin, so for some seniors it can work as a gap year. Life in AmeriCorps NCCC | AmeriCorps
A lot of programs are staffed by Americorps and you may not realize it. Like this one -