I will add this too, just cause, I don;'t know if you have a master power shut off/battery disconnect! or not
but over the yrs I have had a few battery disconnect power shut off switches fail, and as they started to fail, they stopped letting full voltage thru them, , would have a good solid battery and that would run into shut off, but come out of shut off at less volts and amps, which in turn would cause starting issues including the clicking sound you have now!
I now actually keep a spare disconnect switch on hand , as they don't seem to last as long as they used too, cheap junk being made today even the high end models ! be it a 20 dollar disconnect or a 150 dollar one's, been lasting the same for me!, what a shame!
but something else to consider for you!