As I said previously there are a lot of incorrect assumptions about the D&D alignment system. You don;t have to be pure to be good. Good aligned people are allowed to defend themselves and kill people, they might even allow slavery in an environment where you have no geneva convention or prison system. You an also be good aligned an be a coward. ALignment is a tendency not an absolute except maybe for angels/demons/devil etc.
Using the Nazi regime as an example (because its easy).
Nazis prototypical LE regime, you could argue Hitler himself is NE.
A LE person probably likes such a system and seeks to use it. Odds are such a person joins the Nazi party or the military and seeks to advance their personal goals. Any differences they have are likely personal rather than ethical.
A NE person doesn't mind the regime and seeks to exploit it for their own personal benefit. Hitler himself is arguably NE- do as I say not as I do.
A CE person probably doesn't like the system but might be able to exist in it. There PoV however might offend some of the others and they might go to far even for the LE types. Dirlewanger is an example of such a person.
A LN type will more or less do whatever the law is. The stereotypical government bureaucrat who follows orders and runs the trains to the death camps is an example of this alignment. More or less happy most of the time barring extreme circumstances (ie once Germany started losing). Will passively collude with the regime.
N/Unaligned. This person will tend to go along with whatever and keep their head down and try and look after themselves and their family as best as they can. They might work against it or they might not depending on the person. Will passively collude with the regime up to a point.
A CN type won't like this type of regime. If they are a solder they are probably in a penal battalion or getting in trouble with their superiors.
A LG type in a LE system doesn't like the regime but might still go along with it. They will try to change or reform the system if they can perhaps resorting to violence if they can't. They may also try and find roles where they don't have to participate if they can't legally do much. A Soldier or member of the Nazi party requesting a transfer from the extermination squads or posting in a death camp might be an example. They may not have known about the extent of the regimes crimes and they don't want to participate. They might want to change or overthrow the government or they might suck it up and go along with it to a certain extent but make the best of it as they can. Would likely turn a blind eye to family and probably friends working against the government. Oscar Schindler could be an example.
A NG type is not happy in a LE government. They will seek to change it, flee, or perhaps keep their heads down. They might go as far as actively undermining the system. Probably would turn a blind eye to friends and family working against the government.
A CG type is very unhappy and is likely a dissident, subversive or otherwise hates the government. They might not resort to overthrowing it but won't support it in any way except maybe the bare minimum (keep your head down, pay tax). Will likely turn a blind eye to friends, family and strangers working against the government and/or join them.
In any case most people regardless of alignment would not be suicidal and if they have no power as such they would at least pretend to be neutral just to survive if the repression is bad enough.