Hi and welcome to BF. Your plans looks fine to get the motor running again. Measuring by time, not miles, is a good way to go.

Do you have a heart rate meter; a smart watch or armband? It's a low cost way to track yourself and progress. Helped me keep the low stress Z2 rides from turning into messy hammer/rest/quit rides.

I also need to do sessions of strength training to increase my power on the bike. The cycling work is great for the cardio and weight loss, but my leg strength needs the stupid time. Core and upper body get worked too.

Every body is different, so what works for me may not be for you!