Let me put it bluntly, a well-recorded vocal does not require much processing, if you do not have any interface or sound card, you also have a "good" microphone, even the best program for obediating will not help much here. Yes, poor material can be improved a bit, but it will still be poor material, only slightly improved.
If you are serious about recording your vocals, buy at least a good usb microphone (it has a built-in interface), you will spend these three hundred dollars, but you will see what comfort it is when the material is well recorded. In fact, it does not need any major processing, or the addition of some effects such as reverb or delay.
Another thing is the room where you record, good soundproofing is the basis and it does not have to be a soundproof room with screens, I record in the dressing room (clothes act as soundproofing).
I apologize if you did not expect such an answer, but believe me, a few years ago I changed a lot of "cheap" solutions, because for amateur recording I do not need to have a studio right away, and unfortunately these cheap solutions are the most expensive.
I felt sorry for those few words, bought a guitar interface with an XLR microphone input, a good amateur microphone, and practically my audio booth now comes down to trimming and correction of the sound intensity, and I record Audacity.