I had the same problem this morning after downloading the opt-in. I was able to "fix" this by editing the xml-file (in my case YorTechDefs.xml) and removing "<RootNode>true</RootNode>" from the universal translator tech. This only seems to fix it when starting a new game though, my save games still shows the tech as NA (like your screenshot).

I tried playing using your Bugfix Mod, FWN, and it was so far so good until I traded for a kinetic weapons tech to a minor race. That made it so that both the cannon and railgun had greatly increasedmass (28 and 30, respectively), such that my old ship designs didn't work. I tried looking for a "KineticMass" field in the XML for your mod and for the normal game data, but I came up empty. Do you think you could look into that? You're clearly more experienced at rooting these out than I am.

I was playing Krynn, and I think the tech was "Missile weapons" -- it was whatever unlocked the second kinetic weapon

Alright, I've crunched the numbers and done a comparison between kinetic weapons and missile weapons to calculate the comparative nerf between 5.1 and 5.2.

There are 6 tiers of weapons for each and I've processed 3 different properties:

Damage to Mass (DtM): This is the factor, by which you need more mass now for the same punch.
Damage to Cost (DtC): This is how much more expensive it is now to build a given amount of offensive power
Damage to Maintenance (DtT): This is the factor of how much more expensive to maintain a component is for a given amount of punch than it previously was.

Kinetic Weapons:
DtM: 2,3333 / 2,1429 / 2 / 1,8889 / 1,6 / 1,0227
DtC: 2,2 / 1,6364 / 3,0455 / 1,62 / 1,82 / 1,13
DtT: 1 / 2 / 3 / 1,5 / 2 / 1,25

Missile Weapons:
DtM: 1,2857 / 1,25 / 1,1111 / 1,1 / 1,0909 / 1,0833
DtC: 3,0909 / 3,0625 / 2,68 / 1,8919 / 2,027 / 1
DtT: na / 2 / 3 / 3 / 3 / 3 / 1

Comparing these two result-sets we can now calculate the relative nerf. The number here is the factor of how much worse kinetic weapons were hit compared to missiles (if it's below one, then in that comparison they weren't hit as hard as missiles):

Relative nerf:
DtM: 1,8248 / 1,7143 / 1,8 / 1,7172 / 1,4667 / 0,9441
DtC: 0,7118 / 0,5343 / 1,1364 / 0,8563 / 0,8979 / 1,13
DtT: na / 1 / 1 / 0,5 / 0,6667 / 1,25

Which conclusively demonstrates:

Kinetic weapons are now significantly more mass-intensive than missiles compared to 5.1. Especially in the early tiers (how the hell are you gonna fit one of those monsters into a hull of comparative tech level?!) this significantly handicaps kinetic warfare (to the point where I'm certainly not going to build them anymore).

However, they are now generally cheaper to build (maybe not compared to its own state in previous patches, but compared to missiles now).

Finally, the differences in maintenance have hit missile users especially hard.

Note:

These results may give a wrong impression: Both weapon systems have attributes that are not visible to us, that give them significantly different performance in combat. Maybe nerving the amount of kinetic weapons you can fit in a ship was necessary? I don't know about the justification behind the nerf, but my research clearly indicates it was not an accident, thus this is not a bug.

And since it's not a bug, I won't fix it either, sorry.

Note 2:

This comparison doesn't look at the change in defensive performance. Did armor change? Point defense? If yes, how? More numbers await ... but since it's rapidly approaching midnight where I am, they'll have to wait for another day

Word, if it's written in, then no need to fix. However, the devs should be aware that you basically can't have kinetic weapons on a tiny hull as a result.