DocFx could do what you’re looking for. You would write your stuff in markdown and it generates an interactive and customizable site.

we think you’d be best with a bigger team with a better support network

Sounds like they think you’re not independent enough for the position. If it is a small team, they might need someone who can immediately start being productive, while they think you will need more coaching to get up to speed.

No need to drag any disabilities into this.

That’s really useful to know. Thank you for sharing!