I don't have too much time to dedicate to shorter runs but I'd like to keep my jogging consistent. Am I at risk of anything if I just keep a weekly/biweekly running schedule for longer duration instead of shorter runs spaced more freuqently?
Your risk of injury doesn't come from the length of your run, but from its intensity and from external factors like proper recovery.
If you fear injuries or knees problems, you should definitively try with minimalist shoes (you can see brands like Merell, Vibram for Vivo Barefoot for this). This allows to have a natural biomecanic movement, and thus, not letting all the power of your steps traumatizing your knees.
Indeed, you will have shorter, easier, lighter footsteps. The impact will be absorbed by your calves muscles. Your ankles will be free to play their roles (stabilizing). Your feelings and feeback will be much more pleasant.
But beware ! This is a very different effort and your calves will be very sollicitated. You need to re-learn to run with them. Begin very low and go progressively. If you are interested, I strongly advise you to follow this guide : https://us.vibram.com/on/demandware.static/-/Sites-VibramUS-Library/default/dw5f33655e/natural-training-guide.pdf
And stretching is a must if you want to maintain or develop good quality muscles and a good recovery.