I've ascended every class except Rogue and Healer (and neither are really more challenging than Tourist, I just never got to it) over the last ~10 years of idle playing of NetHack 3.4. NetHack is not quite a solvable game, but there are fewer patterns that matter, at high-level play, than one might think. Once you are able to see those patterns (many of which are just part of your standard ascension kit) as part of the game, the solutions generally become fairly obvious and you can just drill through it.

You definitely won't win every time, of course, but you'll be pretty okay.

I found the tourist actually relatively easy. (Especially once you get started.) Archaeologist is supposed to be harder (but I've done that, too).

But that might be because I focussed on the supposedly harder classes after doing Valkyrie and Wizard.

Tourist is hard to start out with, then gets relatively easy. High-level tourists (post-Quest) used to be extremely easy due to the Platinum Yendorian Express Card and a wand of polymorph being able to provide unlimited polypiling (Dr. Efembe, I presume!). Now restrictions on recharging wands and on polypiling take away that advantage.

Archaeologists are also hard to start out, but Lawful alignment, good aptitude for the sabre skill, and a starting tinning kit make them easier later on.

I've ascended without modifying code. I did have to insert a level map from a game in explore mode because there was a bug in the version I was playing. The bug meant that there was a level where there was no up staircase generated.

You can get around that, you just need the right cursed potion - or does that not work if you have the Amulet?

You'll still be affected by the mysterious force if you're in Gehennom, but a cursed potion of gain level will work.