My dragon tree needs help :(

https://preview.redd.it/h62xv0374jn21.jpg?width=1200&format=pjpg&auto=webp&s=882a7402728961cd4dcc9375a0d5ecdfad31c3c1

Hello everyone!!

I got this dragon tree (which i gave a name to haha - Fluffy :) ) for about 3 years now. It was fine during all this time however since 2-3 months ago, when i changed it to another pot with another soil, it .. changed . The tree still grows new leaves at the top, however.. all the other leaves get yellow SUPER fast and fall down. I've also looked at the roots and im thinking there might be a problem there ,or an infection or something, but i'm not sure.

Can you please help me get my plant healthier? : ( If i made something wrong i"m super sorry and want to learn to take care of it more better! I love it very much.. I've added some photos..

Thank you so much for your time !

https://preview.redd.it/7f9yy5094jn21.jpg?width=1200&format=pjpg&auto=webp&s=bd74328b9bb526adf442f910c2acc88d8644cc1d

https://preview.redd.it/w3wnov7a4jn21.jpg?width=1200&format=pjpg&auto=webp&s=af4ab6ca898039cb0bf2bfc4a40868c726ba99b1

https://preview.redd.it/d8zokl1b4jn21.jpg?width=1200&format=pjpg&auto=webp&s=b1140bd6aae66cf448433570926dba2a587a1449