Tajweed courses are not enough, you have to move away from them to the next level into tilawah- that’s the whole purpose of those courses but a lot of people just get stuck there and never get into the active habit of reciting the Quran.
You will improve when you start reciting, and depending on how much Quran you recite otherwise, you will see improvements too. It’s just like skincare, you have to give it time.
Especially when you’re on your own.
Start now.