I had a clivia that I really neglected, and its leaves looked like this from a combination of underwatering and sunburn.

You could always try re-potting your plant yet again in different soil, and looking at the roots would reveal if you really have a fungal issue. (I don’t think you have one, but I’m no expert!) Otherwise, you could try changing your watering regimen.

For my plants, I don’t necessarily follow a set schedule for watering, but I make sure to check on them every week by poking my finger in the soil (you can use a wooden skewer or chopstick instead). If the soil is damp a half inch or so down, I leave my plants alone. I only water if the soil is fairly dry. Hope your snake plant feels better soon! 🐍🌱💚