Try a business valuation calculator, they do pretty well. And also try to estimate it with multipliers of ebitda for example. Try multiple ways to come to a suitable average

Just tell how it benefitted you. I guess even in most failed cases your start up story has teached you some things. Also Most employees like it if you have independence and having affinity with start-ups helps in that. Also jobs like business development manager, even really encourage you to have entrepreneurial experience in that.

What are your yt channels? Here you have the opportunity to share them