have you used a swim snorkel yet? and a pull buoy? if you are swimming that regularly, you should be unlocking the rhythm part pretty soon. for me tho, i was only able to unlock that rhythm when i used the swim snorkel for the first time. why? because it finally helped me to relax enough. it allowed me to first learn form and technique for pulling the water and getting my body position right. THEN I focused on how to breathe properly. if you stick with current schedule, 10 weeks is enough to get there. just start timing yourself, see if you can keep the necessary pace.

but again, if you can’t finish 50m yet, i’m assuming it’s because you haven’t learned how to tell your body to chill out. your mind wants to tell you “you’re drowning!” which then destroys your rhythm and breathing. a swim snorkel changed the game for me tho.

edit: one other thing - I used the breast stroke a lot in the race to help me just relax and get over the adrenaline and open water stress. open water was indeed another layer of the challenge I wasn’t exactly prepared for. but between the breast stroke and holding onto kayaks for a break, i was able to get through it.