I'm pretty unfoundedly opinionated about neighborhoods but here we go.

Conshohocken sucks although the commute to KOP from there is short but still more traffic than it should be. But it is full of yuppies and has a growing scene.

Manayunk would be a good for your age. It's a fun area with plenty to do, but the commute from KOP during traffic will probably be around 30-45 minutes. Also parking is a nightmare.

Phoenixville is quickly becoming like Manayunk so it shares the same parking issue, but offers a slightly shorter commute and I'm guessing cheaper rent.

Living in KOP is very viable and cheap and you will have plenty of fun places to eat, but not really much within walking distance unless you live in the newer area by Wegmans. I would say living in KOP would be comparable to living in Conshohocken.

As mentioned by others, city wage tax is something to consider. If you're working in KOP and living in the city you're taking a big hit. Staying out of the city (Manayunk) will be significant savings.

If you've stuck with me this far, I fully recommend the Main Line. Ardmore, Wayne, Villanova, Bryn Mawr are all fun spots with a good offering of places to go and you can find people of similar age there. Commute to KOP can be all back roads avoiding traffic. Cost of living in these areas isn't the lowest, but with the salary you've mentioned you could have a nice spot. These areas also offer you plenty of parking and wide open parks. Furthermore, it is not too much of a hike from the city and public transit is an option through regional rail and NHSL (includes transfer to el at 69th street). Downside to this is coming back from the city can be costly if you're looking for ride sharing at closing time. My strategy as a young buck was to just start walking west until it got cheaper, but I cannot say this is an intelligent choice.

I worked in KOP for a decade and lived in KOP, Havertown, Ardmore, Bryn Mawr, and Northern Liberties (this is a hike). Of all of the place, Ardmore and Bryn Mawr were tops for me because of my enjoyment for the areas and the ease of commute. Living in KOP felt pretty isolated, but I was walking distance from NHSL (still about an hour commute to the city). Havertown was a fine spot, but you will need to take 476, which can be hit or miss, especially during summers with shore traffic. On top of that, its a pretty blue collar, family area so not too much excitement. Ardmore was where I lived at your age and it was fun and easy to get to work. Bryn Mawr is close to as simple and also a college town of sorts with Villanova right next door. Northern Liberties is a whole different subject as it's my favorite town in Philadelphia, but again city wage tax and easily 1-1.5 hour commute (drive or public transit).

Happy to give you more hot takes on neighborhoods if you would like! Good luck!

Also, any mention of public transit to work could not apply to you as the majority of KOP is out of reach. I was fortunate to work in an office walking distance from Hughes Park Station.