There was yellow fever in Philadelphia, and OTL Georgia did not collapse because of these things.
There was more yellow fever in Georgia. Who said anything about collapsing, though? Pennsylvania had the 2nd-highest population of the colonies, and Georgia the lowest (2nd-lowest when they began counting "the counties on the Delaware"), because of geographic and health factors.
Savannah isn't going to approach OTL Philadelphia as a port for generations in the best case scenario. Beyond Savannah, there is land much less attractive for use by free small grain farmers, no second highly economically useful river like the Susquehanna, none of the same spectacularly accessible and prolific sources of iron and coal. The Spanish are next door and little else is - OTL PA benefitted materially from earlier settlement in and trade with Maryland, Delaware, and West Jersey, both of which were substantial. The native groups are too large to assimilate or succumb completely to disease (or be pogrommed by alt-Paxton boys).
There will be no equivalent great influx of German, Scotch-Irish, and other settlers to TTL's province. The port's not great, the river is worse, the risks are much higher, and people who live around mosquitoes will drop like flies. Yellow fever depressed urban populations in the southernmost states into the first years of the 20th century, and enforcing an eradication campaign was a driving force for US intervention in Cuba.
Geography made Philadelphia a logical site for US capital; I happen to love Savannah, but uhm. Geography made PA the center of American westward settlement until the Erie Canal, and even that didn't alter Pennsylvania's existing cultural impact (e.g. the band of German-speakers that extended into Iowa and defined the Midwest into the early 20th century). Geography made PA an economic powerhouse and GA a series of plantation monocultures appended to South Carolina; a period of Quaker management changes that little. Geography allowed Pennsylvanian political reforms to have profound influence in the early US; not ITTL. Because of geography, Pennsylvania's economy could survive a gradual emancipation law, providing a political model that freed the North of slaves; not happening in Georgia. The Cumberland valley populated the Appalachians and points West in OTL; Georgia will struggle to compete with SC-derived groups for settlement of its own territory. I could do more, but I need to get ready for work.
The early period will be interesting if you're interested in early colonialism. After that, the Quakers, their co-moralists, and whoever else came will be swamped by immigration from SC. Assuming the cotton gin is on time, in a few generations Georgia will be lowland plantations, highland Scotch-Irish, and small, high-mortality cities. As OTL. The state/colony/province as a whole will have a peripheral political role defined by the economics and health factors of the Deep South more than its founders' peculiar ethics.
The impact on the "Civilized Tribes" aspect would be fascinating to explore.
The North would also be quite unrecognizable without the Penns. Germans would remain primarily a trickle into Virginia; the Midwest likely to be overwhelmingly anglophone. Perhaps a few Plattsdeutch speakers will end up in Dutch settlements in East Jersey and New York, but TTL has a lot of unspent pressure for emigration from Germany. Where will they go? No Welsh patches either. The eastern PA tribes are probably pushed to the Ohio or into the arms of the Iroquois relatively early. No big pushes for universal suffrage or prison reform coming out of the colonial Mid-Atlantic in this timeline. Will there be a PA replacement entity, or will the borders be unrecognizable? Maryland might extend further north. The Susquehanna might be an inter-colonial border, or perhaps one province "gets" the Delaware and another the Susquehanna.
The territory of OTL Pennsylvania was much more suitable for small-scale slave economies than New England, upstate New York, or the Iroquois lands - probably the frontier of cash crop plantations will fade out somewhere in the equivalents of OTL southern PA and southwest NJ. Ironworks run on slave labor may become the norm.
I'd read the TL. But I'd watch Penn Georgia skeptically.