id like to add this to the suggestion:
you could possibly make it so that once you failed leveling up a gem, considering you lost both gems in the process which in higher levels, could be an absolute pain to get,
once you failed an upgrade of certain level, the %success goes up by 10% or so, to allow a smoother upgrading experience.
for example; on level 2->3 gems, the success rate is 75%. if you failed, itll go up to 75+7.5=82.5% success. the next upgrade would be 82.5+8.25=90.75%, etc. for that specific gem type, or possibly globally for all gem types of that level.
