I hate to give conflicting advice, but in your place I would start with the Sprint (or Olympic) distance base low volume plan. I did this last year in prep for a half Ironman plan.
If I recall correctly this is roughly 2 Swims, 2 bikes, 2 runs. That gets you consistently training over six weeks - see how that goes before increasing the volume and distance.
Edit: …and join us in the Ironman thread even if you don’t enter this year
