Thumbnails Creation for My Tamil YouTube Videos

I have 2 youtube videos and I need thumbnails for them. The video links are https://youtu.be/3C2lQ_6iVs0?si=YGfHQ2IRRLjzuiul and https://youtu.be/Eu_zRQQMGT8?si=gSc2yuFt3q1obiYL. I teach react prop system and useState in my native language Tamil. This is older video and not much views. I need fresh engaging and attractive thumbnail that could boost CTR. I will delete those videos and reupload it once I got thumbnail. My videos are usually faceless so I don't want any human's face to be attached in thumbnail. Also my channel is very new, I don't have big budget. If anyone interested please contact me. Thanks