The VAST majority of your time in this process is simply waiting months and months for anyone at US Immigration to even touch your application.
And while I haven't heard of US staffing cuts, most federal agencies are currently being trimmed, so this could be even worse going forward.
The marital visa process is the same regardless of where and how you marry.
BUT the Utah marriage allows you to file your paperwork (US Form I-130) IMMEDIATELY (they email you a copy of the marriage certificate) instead of waiting weeks or months before you get the Philippine certificate in hand. Of course, you could also go to any country, say, Taiwan or Japan or even the USA, and marry there and you would be in the same immigration situation. But the thing about the Utah marriage is it's so fast and easy, (only requirements are provide a witness, state everyone's name and pay $50).
You could
I'm not sure it will be any faster. The reason to hire an agency would be because you can't or won't fill out the forms yourself.
My advice would be download the USCIS I-130 form, look it over, and see if that looks like something you could easily fill out yourself.
In my case, I've lived at the same address for a decade, never been married, and file all my taxes on time, so it was something I could fill out in about an hour. Then you wait like a year and a government agent spends a few minutes looking at your forms and approves or rejects them. But the key is getting in that paperwork ASAP to start the clock.