I would suggest doing everything on your own. I learned photoshop to make thumbnails, Adobe Premiere Pro & Photoshop are professional programs that are good to master to improve your editing & design capabilities. You can use these skills outside of YouTube to improve your job standing, resume or find a new job. Look at it this way, mine & your channels are just for fun, chances are it's not going anywhere far, too much competition, but the skills we learn making these videos can actually improve/help our careers paths
I'm good with photoshop to make cool images and make thumbnails but havent really got a clue on how to make a decent looking banner or logo, every time I try to make one it looks too boring which I why I'm reaching out
I do aswell I have also mess with the colour balance and saturate parts, some of the thumbnails on my videos are rushed such as the gang beast one but that was also done on gimp not photoshop because is was 18 and broke at the time
if you really cant do your own just youtube free channal art and type the specific field your youtube channel is about, there are millions of free photoshop downloads you can do, and then just slightly edit to match your channel.
If you really cannot do it, you can get help from some app to design for you. Yes, most people will say to explore by yourself. But when things need much time than you got, it really sucks to just focus on one thing. Make it easier, and chill bro.