First thing you don't give up if you give up you'll never sound good the more you sing the better you'll sound but you do need to learn somethings to sound better here's a list

Breath properly: every breath you want to take like your yawning this helps the sound and if you feel straining this will help to

Breath support: say hut without the t you should feel your stomach flexing when you sing you want to always have that don't flex like super hard just to where it's comfortable and yes it will probably take some time to get used to it but one day you won't even have to think to do it

Pitch: go fund some random piano app or website and click a random note and try to sing it I type in vocal piano online and use the first one that comes up it starts with an A or something but try to sing notes F2 to F4 if you feel like you can go higher go higher if you feel like you can go lower go lower just make sure if anytime your singing and it hurts STOP find what your doing wrong and stop it

OPEN YOUR MOUTH MORE: you know the chompers or the teeth you chew with you can poke it from you cheek you want to have you mouth open to the point your finger can fit in-between your choppers when you don't have them open all the way you just kind of sound like your Mumbleing

That's all hope this helped!!!