How many kids if time is the limiting factor

For those of you who have FIREd and are focusing on your kids, how many do you feel one can have before quality, one-on-one time with them becomes the limiting factor?

We (32F and 38M) are on track of reaching our FIRE number within 5-8 years thanks to the business I've built and want to sell. Our three kids are 4, 2, 0 and my husband and I absolutely love having a big family. We're not planning on homeschooling, won't have extended family around, and my hobbies are outdoorsy (I often bring the kids with me running and kayaking). I'm in my career field due to chance rather than passion and don't feel inclined to continue after FIRE.

We parent with much intent but are pretty chill. So far, having three kids feels 3/10 difficult and there is definitely capacity for more. I deeply value the relationship my oldest and I have forged by going on 10-20k runs on a weekly basis (just started doing the same with my middle child) and want to be able to give individual attention to them all.

I'm guessing 4-5 is the limit, but would greatly appreciate your thoughts.