I would avoid the FAR 135 segment of the industry if at all possible.
I'm at a legacy airline now, but spent the majority of my career in the FAR 135 world. It's nice to have biz jet experience as a fall back when the industry tanks (COVID being the most recent example), but in general I find FAR 135 to be poor quality jobs, not enough regulation and standards and a lot of pilots that, quite frankly, are risky, dangerous and overall not good pilots.
I found FAR 135 to be very stressful and frequently dealt with a lot of drama that just doesn't exist in FAR 121. I'm not familiar with the regionals in the last 15 years, but I regret my FAR 135 experience. It definitely made my career progression more difficult.