Well, let's unpack GPP a little bit and how we could connect it to longevity.
First of all, it's contextual, as it is a prelude to SPP (specific physical preparedness), i.e. GPP is general "physical fitness" for whatever specialized training one is about to do.
en.wikipedia.org
GPP is also not something you do in perpetuity. It's an 'off season' activity to prepare you for the more targeted (and usually harder) later training to reach your objective.
Your stated objective is: "overall health and longevity".
When it comes to reducing all cause mortality and increasing health-span, the typical areas discussed are:
1. Maintaining reasonable body fat
2. Cardiovascular health
3. Musculoskeletal health & strength
4. Stability, mobility, and balance.
So if we then say our SPP is to create a training plan to improve these qualities, one could end up with a program consisting of:
1. Diet and nutrition
2. Zone 2 cardio, with occasional zone 5
3. Progressive resistance training
4. Core work, mobility and balancing work
Of these, crawling doesn't do much to help prepare us for doing SPP to address #1-3.
Crawling might help with #4 a bit, but as a biped, the balance that really matters and may save you from falling injuries is what you can do on 2 feet.
So, no, I wouldn't place crawling as well-suited for the highest level of GPP for longevity, unless it is as a extreme regression for somebody who is infirm or otherwise unable to do more.
And even then, it would be something we'd want to progress beyond as soon as we're able.
If one is fit enough to do KB swings, one shouldn't be in the category of someone who needs crawling as a regression.
If you do, then KB swings are probably too challenging.
My 79 year old mom would fit into this category -- not fit enough for KB swings, so could start with crawling, so she's far from the "highest level."