Trichoderma or mold ?

I had a similar issue few weeks ago when my plants where seedlings. I was watering too much and too often so that mould developed, and it looked just like that. I did remove as much as I could with a spoon. Additionally, I used hydrogen peroxide 3%, one table spoon diluted in a cup of water. I sprayed that once every 2/3 days, 3 times in total and the mould was gone ever since. I’m now at week 9 and I never had a trace of mould again. Hydrogen Peroxide is an anti-fungal and anti-bacterial product, so it will work. Be careful, this is a short term solution, you can’t use it for prolonged times otherwise you will hurt the plants. So use that 3 times, make sure you control the environment, and you will be absolutely fine 😉💪🏼.