Most evidence indicates that OPT graduates create more jobs for US-born workers through business formation than they "consume," so this change would get us further from full employment for US-born workers. See e.g. [0] [1]
[0] https://bw.bse.eu/wp-content/uploads/1564_compressed.pdf
[1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3635535