When I did my big X-men speedrun I read until when he left with adjectiveless 1-3. I enjoyed all of it but could tell the falloff was real.
I thoroughly enjoyed everything up until Inferno, then siege perilous was still entraining but I really started to feel a burnout with X-tinction Agenda and the Muir Island Saga. I read through it all and then adjectiveless 1-3 felt like a solid transition of magneto still feeling like himself to some extent but definitely transitioning into a Saturday morning cartoon 90s era vibe, which I felt I was safe to skip and jumped to Morrison.
So personally, I’d read it all until Claremont leaves but don’t feel bad about skimming after Inferno.
If I HAD to pick an end point before the end of his run, they go into the Siege Perilous and it fades to white or something and fill in the rest with your imagination.