@hssqq Welcome for FPN, and thank you for your suggestion.
I had a look just now, and it seems the BiliBili content producer's calligraphy is mainly in semi-cursive script (行書 ‘running script’). Beautifully done; although I do find it a shame that these days, especially on content sharing platforms and in hobbyist discussion forums, it seems common to unduly focus on particular cursive scripts (e.g. Spencerian for English, ‘running script’ for Chinese) as being representative of call
I highly recommand taking a look at this guy's channel. He is a lacquer pen maker and calligraphy practicioner.
In most videos he uses Chinese xuanzhi, which is the paper for traditional calligraphy, to hold the greater ink flow of calligraphy-oriented pens.