I made a jump from 13" Pro Intel (basically the same chassis as of 13" M1 except notoriously known batterfly keyboard) to Air M1 and then to Pro 16" but also ordered Pro 14" and used it for two months along with 16" to decide which one to keep (because 16" seemed too heavy at the beginning, but then I get used to it, so then I sold 14").
I'm not a native, so sorry for my english, I'll just leave my impressions to help you make right decision:
Regarding higher refresh rate - I just didn't feel any difference, It's just absolutely wasn't noticeable in my experience (unlike iPad Air vs iPad Pro screens where I clearly see the difference in a store) - reviewers say it's because of relatively slow panels on Macbooks.
Regarding deeper black - it's true. 14" just doesn't light zones with black pixels, so they're absolutely black. It's noticeable on watching movies in dark environments but I cannot say that it is critical for me because 13" macbooks also have quite deep black, so it wasn't problem for me, just a nice bonus on 14"/16" models and it makes notch look like part of screen frame cause it doesn't glow in the dart that's fine. HDR is also almost useless for now because of almost no HDR movies on Netflix and similar services. So the most noticeable difference between the screens is in size - but this is slight difference, 14" almost doesn't add screen real estate after 13" - that's why I choose 16" because I needed more screen.
Regarding speakers - they're much better. It is big step forward and they're much closer to 16" model than 13"...
But basically 14" felt significantly heavier than 13" and I didn't like it because I didn't use all this power but clearly felt increased weight and for me It was hard to justify upgrade from 13" Air M1 - I just didn't feel that 14" is ultimately better - it rather reminded old thick and heavy laptops that I almost forgotten... and It also worked less from the battery that also was strange in comparison with much slimmer Air. I can justify this compromise in weight and thickness with 16" model though because of larger screen that I needed and battery life similar to 13" models, but I wish they make Air 15" someday - it would be ideal laptop for me except the sound quality that would be worse in a thinner laptop.