This *might* convince me to upgrade my Sapphire Preferred to Reserve, but I'm on the fence.

This new Chase Sapphire Lounge is airside (inside Security) in Terminal B, correct? (I don't see it on the Massport interactive map yet.) And, sorry if it is a dumb question, but old information abounds online, so: one no longer has to re-clear security using the B-C connector as of 2023? Because I take rare flights on JetBlue, including one next week, which are the only time I don't typically have access already to a decent lounge. I'm generally flying AS or going Int'l.

I have access to the Admiral's Club with my Alaska Lounge+ membership, but that is quite a schlep around the U-shape of Terminal B from the Alaska gates, plus I have mobility issues, some days worse than others. So, while I'm already getting into a B terminal lounge for free, I don't always bother if I'm not feeling great yet don't want a wheelchair escort.

My AmEx Platinum PP will get me in for my first visit gratis; I suppose I'll decide based upon how much I like it. Since I often travel with my teen, paying the $75 guest fee would cover the increase to the CSR annual fee after just a few flights... But now I need to go calculate authorized user fee for CSR over CSP for said teen... Can you hear the whirring from there as my brain works on this one?