Pretty sure 2 factors might make adult game / mod development slower during lockdowns. Imagine being in a house full of people where you have little privacy, and imagine if they didn't know you were a perv making sex games / mods. Usually people go to work, and have certain sleep schedules which makes it easy to sneak in devious hobbies / side projects, but when you are locked in the house with a bunch of people who have no schedule, yeah you aren't going to be able to do what you usually do.
Second factor is some people aren't well off and might of been laid off from their normal high paying jobs due to lockdowns and are now working way lower paying jobs that take up most of their time. And they could be struggling to pay their bills or had to move back with their family in which case refer to what I said above.
