I'm not sure if this has been mentioned before (couldn't find it in a quick search, but I'm also known to be bad at discord search function). It's also possible that this is a limitation from the game engine, but if it is possible, I'd like to suggest raising the resource limits.
Currently I have to return to the secret market after almost every mission if I want to be efficient about upgrading into T4 materials because you can only get one upgrade per resource stack. I'm not sure if this is intended, but it definitely breaks up the flow of gameplay. Increasing the cap would allow for more back to back missions. Another option would be to move the upgrading menu into our inventory screen so that we can do it from there.
Curious if anyone else has encountered a similar issue