If mods asides File Director are still installed, uninstall all of those mods, also clear out the default resource packs.
Launch the game once to install the modpack, than launch it a second time to play it [And get the mods it missed the first time], You may need to do the first step more than once depending on Curseforge's api system.
If the game screams about missing things from Recurrent Complex, just press continue it shouldn't cause any issues, bu8t in the case it does keep a backup [Or reroll back to an FTB Backup]
ALSO if you want a smoother experience toggle VBOS off..
-# For record this is oriented from the perspective of the packs default ram settings and A PC with 5.88GB of usable ram.