I find that the only long term sustainable exercise is exercise that you actually quite enjoy and that gives you something above and beyond ticking a "have exercised" box.
I like swimming but can't justify the time taken to drive each way plus change - for 30 minutes full power swimming I'm driving for 50 and in the changing room for 5-10 minutes including changing and showering after especially if going straight to work after= not worth it. Anything with travel and changing time is similar but worse as I at least like swimming.
In all honesty walking is best for me as I walk direct from my door, no time wasted driving to a gym or pool.
I love walking as as well as being weight bearing exercise (osteoporosis protection) and burning some (I know, not as many as higher impact exercise) calories and distracting me from thinking about food, increasing muscle mass and passive calorie burn 24/7 and improving my waist to hip ratio (currently healthy but it wasn't a year ago,) it's massively important mental health time.
I work constantly varying shifts (can be Monday 6-2, Tuesday 11-8, Wednesday 2pm - 10 am, Thursday 6-12, Friday 11:30-20:00 eyc including weekends...) so I can't have set times but it's essential I find time.
Time is any time the kids are in school or occupied and I'm off work.
Some days I work 12 hours and walk for an hour. Some days I work 6 hours and walk for three hours, some days I don't walk but the kids are home and I do stuff with them, some days I'm off and the kuds don't need me and I walk for 7 hours, some days my eldest or my husband comes with and we walk for an houe to three hours. some days I walk or swim woth dc2 or 3.
Reality as a working parent who isn't an arsehole (usually a man who puts himself fist, second and third, the kids fourth and wife or partner disyant fifth) is that you can work exercise in around work and family,. but can't insist on the same time slot every day.