VAM isn't even close graphically. VAM looks extremely dated and this is despite needing very good hardware to run it at its highest settings, especially VR. Your CPU, in particular, has to be quite powerful otherwise you are running at a seriously degraded configuration.
VAM is highly customizable, however, but a lot of effort, full of bugs, and as mentioned you often have to pay for content. It also completely bars almost anything that isn't essentially vanilla content (yes, some non-vanilla exists but not much). Most content for it is also hilariously low quality which is probably its biggest issue.
If we're talking graphically it would be Afterparty but the game has virtually no content due to being so early into development and animations are not comparable to Operation Lovecraft.
If you like the content offered Wild Life may be worth looking at but it is very niche and, personally, the characters are fucking hideous.
Now, while I say this... because there are not many competitors in the adult space that are even remotely decent (we don't even get to pick from great, only not awful) you have the options provided with little choice, Operation Lovecraft, VAM (Virt-A-Mate), Wild Life.
A tip if you try out brasileirinho's suggestion, VAM. The website Kemono is your friend. It will not have all Patreon and other content that is normally premium for free, but it does have a lot of it. This will save you quite a bit of money aside from the legitimately already free content.
