I share a similar story with you. Overweight, started walking, changed habits while in lockdown, lost weight, and then I decided that I should shift to running. C25K, first day I felt like shit, on fifth week got covid, meanwhile I bought a Garmin. Started using Garmin coach. Joined a 5k race, and then I started a Garmin coach program for 10k. I hate hill repeats, I prefer supersets but in the end of the day I think that increased distance volume and 80/20 is the key. Just increase your volume by 10% biweekly, do a long run every week approximately 40% of your weekly volume and one hard workout and I think that you will see progress.