could use advice, I'm a new chinchilla mom.

I recently kind of inherited 2 chinchillas, really don't the back story on them or anything. I have no idea what sex they are, or their age. I'm gonna take a wild guess and assume my black one is a female cause she sprayed my fiance a few times lol. Neither likes being picked up, but the black one is sketchier than my grey one. Mind you, I've only had them for less than 2 weeks. I of course researched as much as I could about them and plan to take them to the vet soon but could use help on how to idk I guess get them friendlier. The grey one will come right up the cage and allow me to pet her a little and will climb on my lap outside the cage but freaks when it's time to go back in the cage. My black one is finally allowing me to pet it for like 2 secs then backs away and doesn't every try to get out of the cage. Its Almost like she wants love but she's scared. I fear they may have been abused in the past and I want to do my best to make sure they know they're safe now. Right now I've been spending an hour or more every night before bed with the lights off in the room with them just trying to get them used to me and their new environment. Is there anything else I could try? I guess I'm just super afraid of stressing them out, I just really want them to be happy.

P.s. I'm STRUGGLING with names lol and not sure what sex they are throws me off too. That's why they don't have names yet 😭