Part of a 100% full encapsulation is you have to install a dehumidifier and pipe the drain line out of the crawlspace. (9 times out of 10 it is aways put in the most inconvenient part of the crawlspace to maximize the draw. Rarely do you ever get lucky enough that it is next to the crawl space access for ease of maintenance). It also depends on how well sealed your floor is to the living space. There are always holes the pathways for air to move unless you have gone over the top with sealing above the subfloor.

If you are worried about humidity building up in a vented crawlspace, you can opt for adding Crawlspace Fan with a Humidistat to the louver locations. Just don't have all of the fans pointing into the crawl space. Either all exhaust the space or you split it 50-50 for intake and exhaust so you maximize air flow across the insulation/joists.

These fans are sized to fit in a standard sized small vent openings you already have, and most are directional.

https://www.amazon.com/crawlspace-fan-humidistat/s?k=crawlspace+fan+with+humidistat

I agree that calling 2-3 crawlspace companies tell them what your concerns are and that you would like a price to just add insulation, and a second price to do a full encapsulation (or whatever your couple of choices are), letting them crawl through the space then ask their opinion and recommendation. If you get 3 separate companies giving you the same basic information you can make an informed decision based on your climate zone and actual subgrade conditions.