Crawl space fix needed, confused about options- MI

I own an old farmhouse built around 1900. One room has some sagging and it looks like one of the beams is failing. Already tore up a section of the floor, dirt crawlspace under it. The beams are hand hewn lumber, assuming trees taken down on the property. I've been researching for months on the correct fix and I'm overwhelmed at the options and conflicting information I'm finding. From what I can tell, I need a pillar, lally jack, or sister beam. I'd also like to encapsulate the crawl space with vapor barrier and spray foam. I'm not comfortable doing this on my own and from what I've researched, it looks like I'm required to have a permit and structural engineer. Has anyone in MI done this before and know who I need to hire? Is one option better than another? What was the cost? I need guidance from people smarter than I am. Please help!