This is the ickiest romance I've read in a while. He straight up treats her like a sex object, ogling her whenever she was drying her hair, kissing her unprompted repeatedly then leaving before she could even process having been sexually harassed by her superior, staring at her breasts when he believed she was underage, and immediately pinning her down once he learned she was of marriageable age, and now even sexually assaulting her in public before others.
He flat out doesn't respect her autonomy, he never even gave her a chance to decide if she was even down with this relationship, yet he sings praises to his subordinates about how he doesn't want to rush her... And is there really no system set in place to protect such important once-in-a-hundred-year saintesses that the best they could do was immediately toss her into a male-only unit of commoners with dubious backgrounds and do little more than acknowledge that one of them practically raped her? If she wasn't into his appearance, then this would be a very different genre.
TL;DR: Their relationship plays out like a smut manga, but without the smut, so you're just left feeling gross.
Did we even read the same manga like at all ? 'Cause sounds like you're describing a different story altogether. In the first paragraph, for the first point you brought up, he turned to talk to her normally at first. Since she wore slightly baggy clothes and initially bound her chest with gauze , he was probably surprised. Plus, it's kind of hard not to do a once-over when seeing someone with a different look than usual. For the second point, he did it one time from what I saw, and that was after he ate the curry she made and gave her the hair oil. Thirdly, he believed she might be underage, possibly due to her binding her chest because she didn't want to stand out. Fourth, he didn't pin her down until after she said she liked him too, confirming that their feelings were mutual. Fifth, the FL/MC even realized what he was doing; the prince wasn't getting the hint.
Now, in the second paragraph, first, he mostly does, so I don't know what you're talking about. Second, it sounds like you didn't read chapter 5 at all . Third, he was talking about marrying her, cause he didn't want to marry her right away. Due to her sister claiming to be the saintess , they didn't believe she was the saintess. Leon didn't want her to be thrown out onto the street, so he offered her a place to stay, mind you, not for free; she did need to work. Fourth, from what I saw, the unit values her greatly since she improved their meals; as you said , being all male , they were eating barely edible food before she came along. Fifth, Leon did not rape her at all; it was consensual; she was just really embarrassed by the pace at which things were moving. Plus, if she had felt like she was raped, she 1) wouldn't have been happy about what she claimed was the boyfriend's shirt after waking up, despite being embarrassed when she realized it, and 2) wouldn't have said , after being told she could heal her soreness/pain when she couldn't walk right away, "I don't want that." "This is also one of the memorable experiences with Leon-san so I don't want to waste it."