Shingeki no Eroko-san: Hen na Oneesan wa Danshikousei to Nakayoku Naritai

Shindou Eruko, a glasses wearing, big breasted beauty, found a job as a handyman for the Amaguri Handyman service after her NEET life comes to an end as her savings run out. She immediately falls for her co-worker Hoshi-kun on their first day working together, but there's a problem: Hoshi-kun is a high school boy, while Eruko is a 27 years old oneesan who has trouble telling reality and delusional. She ends up constantly scheming to get close to Hoshi-kun to turn many of her delusions into reality...

(Source: MangaDex, edited)