I had one in an office with just office lighting for 13 years and it hardly did anything - and occasional new leaf every few years and one pup if I recall.

After retirement moved it to good lighting and it started to thrive.

I do not know where you are, but the plants are telling you they are in the wrong place. I too, have had soils like pottery clay, and as long as plants were in the GROUND and not in CONTAINERS it never seemed to make a difference no matter what books said.... I am including tree sized Euphorbias, and some other unlikely subjects....I think your plants are not getting enough light to inspire them. I have a small case of suspended animation because i brought my Sansevierias indoors out of the unheated greenhouse in the frigid Southern California winter, and they are now just THINKING about making some pups..if the nights warm up a bit more and I put them in the greenhouse with real light, much more intense than what they are now getting, i predict a frenzy of new growth.

Change the soil, and that will give them a jump start.
Also I have been told they like a slighty acid soil, perhaps African Violet/Orchhid med. size soil mixed with pumice or it's equivalant substituted. (small cracked clay pots, small rocks, chicken grit, cracked shells, or??? what ever you have. Don't forget air circulation, they come from
Africa so grow in very sandy coarse soil that drains very well, so grow out on open plains hiding in the grass, some under the trees. they only get water when it rains. Some live in ancient coral beds, other are troopical. So use your judgement and you can't go wrong. Norma

Fertilize then give a lot of water every week. Try a little vivagar in water. Some like a PH that is slightly acid. The soil, may be missing the minerals that they get from the coarse sand where they came from. We need minerals also and so do they. Norma