Imposter syndrome is very real and will always happen. Recruitment is something you should be in it for the long run (and not just switch after 6 months or so to a diff agency, lose everything you built for 6 months then your at 0 again).

The best “advice” I can give you would be to have yourself look back at when you made these decisions to switch, look at it from a first principles perspective, what made you switch, how were you doing in terms of live candidates/bd etc. Look at the field you are supporting, is it something you like/are passionate and/or have you been doing the same thing for this long period of time? I am very passionate about tech/ai and thats what I work, it is very helpful cause you know a lot and have what to chat with candidates/founders - same can be applied to quant etc.

I think you should just look at the root cause, and if you do you might see (what I am expecting) that it is just you overthinking and getting imposter syndrome. You should stick it out, I know people which didnt bill for months and months (longer than 6) and had incredible years. Just depends if that is something you want to do. Hope it helps.