Have I missed something? - Your advices much appreciated

Am thinking of buying a mirror-less camera, for its compact size, good image quality and lenses adaptivity (We have a couple very old EF lenses sitting in a drawer for many years.).

For the past some years, photography wise the family gets by with a Nikon D5100, a couple compact cameras and iPhones. For our most recent overseas family holiday, we struggled for packing and did not bring the Nikon. It’s kind of a wakeup call - and why we are thinking getting a mirror-less (which will be used as our primary family camera, together with iPhones).
I looked into several Canon models and did some test shots.

RP:
The size is similar to a Nikon D5xxx, a tad lighter. Full frame is obviously the largest feature. They put on a RF 24-240 lens and immediately I said no, due to its size - bigger than the Nikon + lens. Too expensive as well.

Then I tried some smaller EF lenses with the adapter. IQ was very good as expected. Though the other Canons tested also produced very good photos. If I zoom in the comparing photos to a ridiculous level on the computer, do I see better details from the RP photos? Maybe for some. But that is when it is only displaying 1/100th of a photo. In normal size viewing, for most photos I would not tell the ones from RP as better.

With RP the size would not be meaningfully smaller than the current Nikon, and the battery life is the worst in the pack. Being full frame, it does not come with built-in flash. We found flash useful, like on holiday shots where its back-lit. Another inconvenience if need to bring an external flash.

SL3:
The smallest DSLR. Test shots were as good as other models tested. Do not need adapter to take existing EF lenses. Built-in flash is as powerful as current Nikon and battery life is the best.
SL3 is obviously not mirror-less, and still bigger than M50 or M6-ii.

M6-ii:
The newest in the M series, better than M50 on several specs. Small, compact yet powerful. IQ wise identical to M50 in my test shots. High speed continuous shooting was indeed very impressive. IQ was brilliant in such high burst. I know 14 FPS is great, but dont know how often I would use it.
Costs almost twice as much as M50 though. The power of the built-in flash is less than 50% of that of the nikon or SL3.

M50:
Great IQ in test shots, equally small. Built-in flash is similar to M6-ii (so are a number of other features).

The guy from the shop said should go for either RP or M6-ii if possible. I am leaning towards M50 and would like to act within this month.

However, I never had a Canon DSLR and not know much of Canon cameras (did use a Canon Powershot A610 many years ago, a lot great photos from such a humble camera). Wondering if I have missed something which would have meant RP or M6-ii a better path to go down.

Mostly family use - holiday trips, family gatherings, birthdays, kids’ school events…etc. Sometimes may shoot kids sports but less and less now and several frames per second would be OK. They are growing up, not many years away from high school graduation - so there will be some ceremony moments to capture.

Any opinion / advice on what you think is our best choice and whether I have overlooked some important features on RP or M6-ii or another model is much appreciated.