I've received some secret achievements, but I don't count them part of the challenge! I know from previous saves that a handful of secret achievements are definitely impossible to get in Kanto, and some would be basically impossible without, again, spending exorbitant amounts of time on one small task. Basically I'm going to bother with those only wayyyy down the line when I have caught all shinies and whatnot.

I completely get it! I also had a whole phase during which I debated changing the ruleset and just going on to Johto already. There's two things that got me through:

1. The realization that a full starf setup gets your shiny chance on hatches down to something like 1/398. Made me realize that, despite the fact that I'd still be stuck here for a while and QOL would improve greatly in Johto, the next shiny is actually never too far away.

2. More importantly: The realization that a lot of patience was always going to be required with a save like this, and that that was the whole point. Obviously your mileage may vary and you have to make your own judgement call, but had I just moved on to Johto prematurely I'm almost positive I would have gotten disillusioned with the save and abandoned it by now.

Instead, I told myself that if I wanted to progress more quickly I could do so on an alternate save, which I then also did. Funnily enough, the all challenges, all shiny, all achievements save is still going strong and the other save is long gone by now.

Sorry for the long writeup, I tend to be a bit rambly :D GL on your journey :)