After stropping, I just very lightly touch the edge with my thumbpad to sense if it is "sharp enough" before stropping more. This comes with experience. Facial hairs are thicker and coarser than other hairs on the body. So they take more technique to get a BBS (baby butt smooth) shave.

Technique is a big hill to climb, but well worth it. Go lightly and multiple passes tend to give the best shave.

Perhaps taking steps to shaving some of the face with a straight razor is better than trying to shave the whole face initially. Then build upon the success in sections.

Keep trying and referencing the Wiki and welcome to SRP and straight shaving.

Pabster