Help with defective ignition switch?

Civic coupe vti 1999.

Car has been stalling recently and am thinking it’s due to an ignition switch. I had recently swapped a previously faulty ignition switch with one from a breakers.

I assume it’s the switch because when car stalls I can see the green key symbol flashing(which shows security is enabled I think) and I usually see this symbol when I switch the car off/turn key to off position.

I noted yesterday that after two repeated quick stalls just holding the key in start position for a little more brought the car back on. I know if you need to always do this that’s how you know it’s a ignition Switch problem. I haven’t tested this repeatedly(unlike before) and didn’t have to hold it long unlike last time.

1. should I assume it’s the ignition problem in light of green key light flashing on stall and getting it to start by holding longer(after two repeated stalls) on one occasion? Don’t know how many repeated stalls I will need to get where I will have to hold on start for longer to be clear that it is absolutely same as last time.

2. Car performance is down and sluggish. Could this be related to the ignition switch or is it likely something else?

3. Are there any wires/connections I should check which could cause this rather than the part?

4. The switch I am using was from a breakers so could have been old to begin
   With. However about two months ago car was constantly stalling immediately to about 30 seconds later. I cleaned up corroded battery terminals and this problem disappeared. I read that a good battery could prevent a defective ignition switch but the article was t clear. Could trying to run with the corroded battery terminals have lead to the ignition switch deteriorating which has caused my current problem?

5. How would I know if it’s key cylinder rather Than the ignition switch that needs replacing?

Thanks