While I personally use Ubuntu on my laptop for several years now, when I helped my relative with a brand new laptop (huawei) with Windows 11 I was suprised how fast it was despite being very cheap, I don't remember any version of Windows that had such a performance, at least visually. Out of curiosity, what model does your father have?
It's a Lenovo Yoga 9i with an Intel EVO i5 CPU. Not sure how much memory it has.
To me it's generally pretty quick outside of File Explorer. The reskinned File Explorer is an absolute car crash - it's like they've taken everything that made 2005 KDE awkward and bolted it on top of Windows.