Please tell me about electrolytes again

I just can't seem to get them right... I've been on keto 5 months now and I still get foot cramps in the middle of the night. I take 3 LMNT sachets a day plus 2 Swisse brand magnesium glycinate tablets and half a teaspoon of Lite Salt in my food. I ride a bicycle a lot, hence the foot cramps, plus weight training 3 times a week, but I thought my supplements should be enough?

Some numbers: I'm 6'4" 272 (1.94m 123kg) and if I add it all up my total daily intake is:

Sodium: 3900mg, Potassium: 1050mg, Magnesium: 480mg

Should I be increasing something? I'm also probably due for a podiatrist visit, too much cycling and flat feet, I might need some arch support or something.

Follow up: Following recommendations below I increased potasium and sodium by adding lite salt and table salt to my electrolytes before bed (1 tbspoon each), and it did work, no cramps last night! The downside is it gave me such an energy kick I couldn't sleep until 4am. I probably need to reduce the salts and maybe take it earlier, I'll experiment and figure it out. Thanks all, much appreciated :)