Which iPod or alternative hardware?

I am looking to plan for the replacement or my iPod Classic, 6th Gen - 160 GB - (although my iPod Nano 3 Gen is still going strong, battery charge issues apart, so it might be premature re the Classic). I have no desire for an iPod touch whose features, other than music (even if I did not have an iPhone), I would have no need off and probably be unable to use for the most part, especially given cost without - apparently - the same sound quality. My iPhone has no capacity to store more than the odd playlist or two, and usually cannot access a source from which to stream music.

My criteria are: sound fidelity (NB my 3rd Gen iPod Nano sounds considerably better than my 7th Gen iPod Nano),
compatibility via dock cables to my extant Hi Fi/sound systems
storage
relative affordability (I no longer am able to work as have a Carer role for disabled relative).

I have an excellent Nikon Camera, limited wireless functionality at home, and limited phone signal anywhere local.

I like the functionality between phone and MacBook (calendar, notes, reminders) and I use my phone to check emails when out and about, but rarely to phone, occasionally to text. This latter depends on reception. I get no phone reception in my house and for the most part in my neighbourhood. I have poor wi=fi in the house, and if two people are connected in the evening, usually one needs to be connected via ethernet. Close to Lifeboat station/harbour masters. Indeed even radio is only reliable in one upstairs, back bedroom: Rural Scotland, granite, dip/hollow for natural harbour.

My iPod Classic 120 GB (2/3 full) is usually plugged into one of various stereos (as auxilliary device) and stores almost all my music which I have either ripped or bought via Apple Store, though I have about 200 CDs that I have yet to rip many rare recordings or festival performers not on Apple Store - whole different rant about when Match replaces them with something not the same - (I still have a CD player, vntage 1994, and a Technics amp. 1997, and very good quality Jamo speakers from the same era; I have a cheaper stack system elsewhere with good speakers and a ViewQuest radio with a dock for Classic & external middle-range quality speakers).

I am melded to Apple only because all my devices are Apple and (when I started photo editing Apple was best choice).

I continue melded because, well, even Window 10 ***** in terms of responsive and (my son's) Window Laptop recently purchased at a price similar to our last MacMini is left in the dust by that MacMini in terms of the Iris Intel graphics alone - and the functioning speed, WITH 400 Gb of data (over the new Laptops close to none). My 2012 MacBook, too (upgraded RAM to 16 GB), though there are many bugs with El Capitan (not least Parental Controls conflicts).