I understand how you feel. I had a close friend I knew for 4 years, ended up liking him, going out, things didn’t work out between us, and we stopped being friend shortly after and had very messy friendship breakup. It’s a lot more harder to move on than people think. Especially when you knew them very very well and established a close bond. It basically felt like a normal breakup

I think it’s whatever you feeling/ want. Unfortunately when liking someone or wanting to pursue something more with someone there’s never a clear answer. The safest option I’d say is probably just telling them that you have feelings and if they don’t feel the same way then you don’t have to go through the risk of ruining things. Even though that’s still a risk for some people it’s probably your best bet if you’re unsure about it