I admit ur pacing is too fast but whats done is done so even if u will end this novel prematurely at least it will have ending or u could just make mc travel to different world and somehow make him seek new power or nerf him a little bit, i suggest going to dxd world or campione.
Now take his harem members as well if he went to dxd make him reborn as issei to get boosted gear but make him a new faction leader rather than typical devil maybe make him demon rather than devil just like meliodas maybe? 7 deadly sin or 10 commandments.
That should prolong ur novel, just my idea no need to rush as long u dont drop every novel u created...
continue the work..
<inner thoughts>
shameless author don't you dare stop this non vel or i will kidnap you and place you in a close room with only chair, table, pen, and book and order you to write the novel non stop...
Leixein