side quests

[Tech Damage]

at what point in the game is the cut off point for completing sidequests? im in cargo bay right now during the lockdown and still have a bunch of sidequests

[RaZexxBomber]

Usually there isn't a "cut off point" for anything unless you complete the game without saving before hand. But you can always find some way to go back and complete the quests.

[Fifty Three]

Areas of the game get locked off after meeting your brother in the Arboretum after stopping Dahl and Kaspar.

[L4z3r]

Dont worry you can always reload saves

[Animeye]

There are a couple quests on a timer (just check the mission log, it will show the timer if there is one. By cargo bay, I think you've passed all of them).
Otherwise, the "point of no returns" are as follows:
Soft (you can still backtrack fo rmost things, but it is significantly more difficult): when you turn in the coral scans
Hard (you are cut off, and the game explicitly ends the missions): when you open Alex's hiding spot

As you are noticing with the lockdown, there are some periods where areas will be locked off/harder to access, but as far as I'm aware the only actual "no return" points are the two listed above.