Chin-Ups and Pull-Ups

I have a few fitness targets I would like to achieve by the end of the year:

Completing a full-marathon within 4.5 hours with a maximum of 5 hours.

20 Pull-Ups and 20 Chin-Ups at seperate sittings.

So far, my training runs are progressing well. 4.5 hours gives me a buffer of 18 minutes at 10km/h, so I don't see a major problem achieving a sub-5-hour run.

I have so far achieved 11 pull-ups and 16 chin-ups at seperate sittings, so I will probably be able to do 20 pull-ups and 20 chin-ups before the end of November and I'll probably will change my target to eventually do all 40 pull-ups and chin-ups at a single sitting. It's gonna be a killer, so I'll probably will try for 15/15 or 10/20 or maybe 20/20 with a 10 to 15-minute break in between tries.

Six-pack wise, I'm seeing a little bit of them. Right now, I'm hovering at 54kg. I've been trying to get down to 50kg for the marathon, but with all the compound body exercises I've been doing, I probably have been gaining a little muscle too. Here's hoping that my six-pack abs appears by the end of the year.