https://www.ebay.com/itm/126989965296

This is a rare one, only one I've ever heard of was his, time to get it now before the end of the month.
I was asked to post this for him, get it now or never.

I'd consider this if there's any way to get a test disc.
Nevermind, i see has a test disc for sale as well.

Is this very difficult to use?

Not sure, never fixed any players other than cleaning a lens here and there.

This is an interesting device. From what I could read on the Ebay listing briefly, it seems to allow the focus and gain adjustments (and maybe others?) to be done potentially easier and/or faster, and without an oscilloscope. If you ran a Pioneer authorized service center or similar in the 1990s, and you had lots of players coming in and going out regularly, it could have been a big advantage to have one.

The standard alignment procedures with an oscilloscope and other standard tools do not seem to be that complicated or tough, though, especially once you have some practice and experience. Good oscilloscopes were US$700-2500 in the 1980s and 1990s, but now it is easy to find nice used Tektronix and Hewlett-Packard scopes from that era at bargain prices.

An interesting piece of Laser Disc history indeed. I wish I had bought a spindle-height-adjustment jig from Pioneer for my VP-1000 player in the mid-1980s or so. (That is what Pioneer's USA service department said I likely needed to adjust, to fix my player's crosstalk issue.) But its US$75 cost then was like spending $1000 now.

That device looks like it would be easy to duplicate with the appropriate documentation.
You could likely get it from some Chinese custom manufacturer for 10% or less of the price asked. Unfortunately we don't have that information

Probably but one would have to buy the unicorn to remake the unicorn