Hey y'all, I used to do competitive swimming from ages 13 to 18. After that, swimming remained something I'd do once in a while. Now it's been years since I've done a serious swimming workout or swam for a workout at all. Instead I've kept myself (reasonably) fit through running, cycling, gym workouts, rollerblading, and most recently, kickboxing. This year I had about 9-10 months of sedentary life for a variety of reasons, with no exercise beyond walking around my town a little bit each day. Without any additional exercise, it really screwed my mental health and fitness, and it took a lot just to motivate myself to get back into things. I just started to get back into running, but it's been really tough on my knees, just as kickboxing was tough on all my joints, and I've been thinking about sticking to cycling and getting back into swimming for now until things feel better. I also am still building back stamina for cardio in general. To make things even more wild, I have gone through over 3 years of hormone therapy, and so my body has changed quite a bit and overall I can't perform the same way I used to due to that and age. I am essentially "re-learning how to use and build my body". Which brings me to my questions:

What are some good ways to ease back into swimming for personal fitness (I don't plan on going back into competitive swimming ever again)? Are there any workouts that are well-suited to people with past swimming experience, but not over the top and focused on building back up endurance and re-conditioning? I'm paranoid I'll slip into that mentality of pushing myself to the brink and over-doing it, getting mentally exhausted, and burning out. I used to do practices on the order of 7-8000 yards avg, and I'm not seeking to go back to that. I would be happy just being able to work up to 1000-2000 yards again over a few months and call it good. Maybe this was way too much info, but yeah I'm mainly looking for advice on how to ease back into things in a healthy way.