The definition of PanchAmritam from Scriptures (took this sloka from Nitya Karma PujA Paddhati book) is:
Dadhi Dugdham Ghritainchava Sarkara Samyuktam Madhu |
PanchAmritamidam Proktam Vidhayam Sarva Karmesu ||
Curd ( made out of Cow's milk), Cow's milk, Ghee, Sugar (sarkarA) and
honey all mixed together is what constitutes the PanchAmrita. And it is prescribed to be
used in all rituals (vidhayam sarvakarmesu).
Now, if procuring honey is really an act of depriving the bees or an act of Adharma then the Scriptures will not prescribe it's use to start with.
So, your apprehensions are without any valid reasons IMO.
Also, substitutes for objects used in rituals are only prescribed when those objects are expensive, hard to procure or difficult to apply.
For example, for satiating a malefic Saturn in one's chart, the Scriptures prescribe donation of a black buffalo (which is difficult to procure for some) or donation of blue sapphire (which is expensive).
So, in such situations, it is rational to expect that there will be substitutes and there is indeed such substitute and which is nothing but offering a minimal amount of money instead.
But, in this particular case, all the ingredients of the PanchAmrita are easily available, inexpensive and easy to apply as well. They are present in almost every households.
So, i don't think there will be any substitutes prescribed in Scriptures because there is no need.
You can continue using honey without any negative thoughts.
Adding a passage from the Varaha Purana, which should clear your doubts.
PREPARATION OF ‘MADHUPARK’
While describing the method of preparing Madhupark, Lord Varaha told
Prithvi–“Madhupark” manifested from the right half of my body at the
time when the process of creation began. This is the reason why it is
so pure. Anybody who makes offering of Madhupark in the course of my
worship,attains to my abode. For the preparation of Madhupark honey,
curd and ghee are mixed in equal proportion. While preparing it sacred
mantras in my praise should be constantly chanted. Giving some
Madhupark to a dying man liberates his soul.”
So, there is nothing wrong in using honey, as the scriptures are approving it's use.