Replying to Fill tilt dropkick 2015/16. New boots or liners?

I bought them as my first pair of boots, they're 27.5 and used to fit perfectly. Since then I've skied two full seasons (everyday for 20 weeks straight) and the liners have been recooked to death.

They no longer fit as well (some moment in the heel) and they're not as warm as they used to be.

I don't know a huge amount about boots so was wondering if it would be in my interest to find another boot that fits or buy a new liner like "Full Tilt Full Tilt Pro Liner 2018 white"? Money is a consideration but I'm heading back out for a another season so warmth/comfort takes priority.

Thanks for any help