As it is now, you have to pay gems to reset the entire skill tree of your geologist or explorer. I suggest that we get an option to reset the trees in parts, from the highest to the lowes.
So for eg, you could reset only your codexes, for a smaller amount of gems. If you wanted to reset your tomes, you'd have to reset codexes first, then tomes (otherwise you could exploit it to have a full codex tree but no tomes). And there should ofc still be an option to reset the entire tree, preferably to a lower "total price" than resetting all parts separatley.

Having to pay 1000+ gems to get back all your books when all you want to change is a couple of codexes feels a bit excessive, and I think that more people would use the system (hence, paying more total gems and maybe making money for BB) if you had the kind of option I described above.