Short list of some small potential changes to discuss:
SACUs only have access to t1 and t2 unless they have the engineering upgrade which grants them t3 t4 as well as extra BP. At the very least it would force UEF to get the engie upgrade if they want to Rav creep.
Engineering upgrade gants extra build radius (discussed on the discord a while back https://discord.com/channels/197033481883222026/1236147386141904988).
Gateway adjacency changes, maybe even including changing the size to fit more or less adjacent buildings (Would 8 t3 adjacent fabs be overpowered, or is that enough risk of a chain reaction plus setup cost to be fair?)
Nerfing RAS so the mass generation goes from +10 to +5 (ontop of base +1 from the SACU) but also lowering the cost to the payoff time is the same, but now you need to spam twice as many to get the same total income, meaning you have ~twice as many things to defend from incoming fire, which combined with the base health nerf should mostly satisfy people complaining about ras bois being op.
Removing the income generation of SACUs without RAS entirely so now your not paying for uneeded stuff when building rambos.
Some upgrades cause SACUS to death nuke harder, things like teleport or gun upgrade, thigs that you wouldnt get unless you are expecting them to end up in enemy territory.
Replacing Sera overcharge upgrade with a Refracting Chronotron Amplifier so multiple can be used at once without needing infinite energy.