CROSS APPLY instead:
Making OUTER and CROSS APPLY work for you[^]
select * from @entities as e
select top(1) act_finish_time_local, oper_id
from job as cleaningJob
where cleaningJob.oper_id like '%'+ e.ent_name +'%'
and cleaningJob.act_finish_time_local < e.startDT
order by act_finish_time_local desc
"These people looked deep within my soul and assigned me a number based on the order in which I joined."