A sub-domain acts like a normal domain, the problem you may find is people looking for your brand etc. so if they type out the URL and go to our company.com which could lead them to a different site etc. So in short you can still rank it fine though its perhaps a bit more complex, I would look at it from a user point of view and a branding perspective and go from there.

Personally I may agree with you on moving to a .co.uk (assuming you are aiming at UK markets) just so its not on a subdomain and its a bit easier to brand etc. but SEO wise its still possible to rank uk.com

Hope that helps a bit, Good luck!

in short no.

new TLDS can rank just as well as any other TLD and the .uk is treated essentially the same as .co.uk so as long as you're doing good SEO you shouldn't find it hinders you.

https://moz.com/products/api/keys

It really makes no difference as they would both be around the same, I would recommend YouTube as it is another search engine giving you even more opportunities to be found.