Give it time.
I borrowed my BIL's Trek 1100 to start out riding. Like only 10mi a time in the neighborhood. I thought I'd take it with me for work a few times that I had a week at a time down in Greenville SC. Greenville SC has that nice trail system. It also has Paris Mountain.
I had done maybe 35 to 40 on the flattish greenway there a few times, still feeling totally destroyed.
I decided to try the mountain. It's "only" like 800 feet or so. LOL! I had to stop three times on the side of the road just to sit and pant. A roadie going up the mountain was even concerned and almost stopped when he saw me! This Trek 1100 had a triple on it also. Pretty sure the easiest gear was a 32/28. Not quite 1:1, but close.
I kept at it. A year later it was our last work visit down there. I went at the mountain again. But this time I was doing a climbing workout where I went over and back twice. So climbed it 4x for the workout.
Just a year made that huge difference. You can do it. Patience. Have fun!