Breaking the Provost will allow some more unlocks. You should be able to buy one from the kidnappers.
Have you interrogated the stargod coordinator or public enemy yet?
There are a few tech bottlenecks, especially in the late game that will rely on getting a few particular enemies or interrogations and or items (ie, implosion bomb launcher). These can be locked behind RNG dependent missions. It maybe worth firing your research team, then hiring them back when you have more options.