What is the safest thing to use when it comes up to having your house smell good while being pregnant and soon a newborn?

I think my house doesn’t smell the best even after deep cleaning it. The worst areas are the bathrooms because the boys leave pee splash or don’t flush the toilet. I have a wax melt because I feel it’s a bit safer with my feral boys but it takes forever to melt and make the house melt. The one I had is ceramic and I accidentally broke one. I would rather have a plastic diffuser but I’am nervous about essential oils and causing any kind of damage to my boys and myself while pregnant. Essentially and importantly when my baby is born very soon. I’am scared it’ll cause asthma or something serious. I want to leave something smelling good for long hours while we are home. I would if anyone knows science based things and safety things when it comes up to kids and scentend things. Thank you in advance!