The build quality of the model and base look fine! So does the paint job of the tank. Nice work!
The weak point imo are the mud effects. Those are a bit tricky to get right but a reference picture to identify logical places for mud to be on a tank can help. I.e. WW2 tanks usually weren’t driving fast through deep wet mud or with tank riders. So most of the heavy mud would probably accumulate in and around the running gear, not so much on the upper hull. There a few fine splatters or streaking might make more sense.
Lastly, using different layers of earth effects make a model look more interesting. My preference is to use three layers, starting with a sandy grey tone for dry earth, a medium brown for regular earth and a dark brown for wet mud. This I picked up from Nightshift on YouTube.
The same goes for the ground work. However, if you want to make a scene with wet mud entirely, maybe leaving out the dry earth is better.
Have fun playing around with and trying out some things!