I'd personally play something else and just wait for the next update, but if you want to prepare for the next update in advance, the levels will probably go to 2000+ looking at the Infinite Corridor's scaling method. It can be assumed that there'll be 10 floors per remaining Touhou boss since that accounts for acquiring all of the Awakening items. The level scaling currently has bosses gain +36 levels every 10 floors, so that would account for 49 * 36 = 1,764 levels, +600 from the 100f boss would be level 2,364. That's only a projection based on how things currently work, there might be changes in how the Infinite Corridor works in the next update.
As for equipment, that stuff at least has been fully explored through exploring the game's files, but the stats shown can't be taken to be finalized, as there are some discrepancies in what was originally found compared to what was implemented. Taking the
reward item for example, the stats were originally listed as HP/DEF+999%, ACC+99, DRK+300, but the final stats are fairly different, being HP/DEF+1080%, ATK/MAG+400%, ACC+66, DRK+300, DTH+150. As a smaller example, Scourge went from ATK+880% and DEF+440% to ATK+800% and DEF+400% (both versions have PHY+100).
Looking at the old list of items that were found in the files, the ones that haven't been implemented in an attainable fashion are as follows,
First 4 are page 11, after
are all the items following the
reward item. From this listing, it's probably safe to assume that equipment like Quartz Charm, Regalia, Medicine of Life, and Machine God Lucifer will remain very relevant even once everything is available. idk what else you might want to farm, I guess you can always just acquire whatever you intend to use while playing through the rest of what will be left of Plus Disk in the next update.
There's presently 6 achievements that aren't acquirable right now. I think these are the correct name/objective matches, but not 100% on it. Translating them roughly, they're
If these titles grant the last 6 items on the list, then that likely means
There's also a lot of songs that aren't yet used in the game, enough that I can't figure out what they would all be used for. Specifically, there are
songs that seem to be unused. Who knows what could be done to fit all of those songs in, considering there's only
floors unimplemented yet. Can guess the purpose of some by names, but that's about it.
Can't think of anything else to say about what the next update might have in store.