The Geo TBs are aimed at G13 - fully expect the later missions to be impossible without characters at G13. Moving mods to creep over the entry barrier isn’t going to do diddly squat. Just gear your characters that are needed.
If you really were planning ahead rather than being reactionary you’d be stockpiling G12/12+ to gear the characters needed for the Geo TB. At the same time as farming mods (3-5 daily refreshes for mods and/or slicing material) to diversify your mod selection for GA championships which alongside Geo TB is going to be the gateway to the G12 Finishers.
