Question about events

It seems you're overthinking it.
There's really no time limit in completing the game. Just play at your own pace. If you're stuck on a level and don't want those level 90 10/10/10 Zhuge Liangs' help, go do Free Quests and rack up some experience, quartz, and materials while waiting for an event.
Also, anyone can participate in events as long as you finish the required singularity (mostly Fuyuki), and level of Servants barely matters in it.
Simply, as long as you put enough dedication to farming the materials, sooner or later you'll be swimming in it. Hope this helps.

Worry not. Im playing the game for one month now, and during the Onigashima event i was worried if i can get 100mil dmg for Sakata Kintoki Rider ascension materials. My servants were lvl 60 and i thought ill strugle with it. Well, i was wrong. Turned out i dealt 500mil dmg during the event.

I suggest you at least have 3rd ascension. There will be future events with harder content but you should be ok at this pace

"My main party is all arround 40/ 50 yet no ascension in sight, because of items."

History of my current FGO life, bro...except I just ended London, did abuse supports on the Four Devoting Pillars because f*ck that boss, spent 3 command seals to ressurect every1 at 100% NP and still got smashed afterwards.