Thanks for the response and clarification, even on such a basic question. I think I may have characterized the external GPS wrong as it's not an antenna per-se but a gps puck (the amazon listing is here). I was under the impression they are separate GPS units.
I just spent an hour or so outside with the stratux for calibration and locking satellites and what you said now makes sense. It appears the internal GPS had ~3-4m accuracy and then the external drops that down to 1.5-2m or so. So having the option to move the GPS location out of the unit definitely seems beneficial to getting better accuracy, I think I will utilize if I have a trip where the accuracy is needed.
Clear skies!
Was I expecting too much to think it would work fine?
Yes.
You might be able to drill a small hole into the case and mount this pigtail for an attachable external antenna: https://www.amazon.com/Stratux-GPYes-2-0-External-Antenna/dp/B07NDPXDDY
I got this gps: https://www.amazon.com/gp/product/B0716BK5NT/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
My understanding is that it has a port where you can choose to wire in an external antenna (not usb). This is the antenna,it also includes a small wire to attach between the gps and mount to the case:
https://www.amazon.com/gp/product/B07NDPXDDY/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
Note, it was mentioned by others the picture on amazon for the gps is old, I read all the gpses v2 sold from Stratux store on amazon have the needed antenna port, the v1 version does not.
Hopefully, if it works how I imagine, the internal antenna is used unless the gps prick is plugged in, then It automatically switches to the external antenna, no configuration or other hassle needed.
I will get the parts today, although with my small kids around who knows when I will get a chance to actually build a Stratux.
This is the low power SDR I was talking about:
Here is the GPS antenna I am talking about:
https://www.amazon.com/gp/aw/d/B07NDPXDDY/ref=ox_sc_act_image_3?smid=A1FY2FJYL6LK7D&psc=1