IPeng laggy on volume & song changing over LMS

I am really struggling here with this now as over time I’ve got this issue I didn’t have previously - it’s crept in somewhere - maybe a software update too many on old equipment?
* I need the variable volume over the app as my amp is not remote volume.

So:
• Changing volume on the iPhone doesn’t immediately change the actual volume. Then, a minute later it will ‘jump up/down’ depending on what I slid the volume to last. It use to work all the time but this happens after a few adjustments. Then I have to ‘refresh cache’ on the iPeng app. And on it goes.
• Selecting a different song/adding to playlist etc as above: becomes unresponsive after a short while until I ‘refresh cache’ on the iPeng app.

I don’t know if it’s:
• The Squeeze Box Touch/software
• The NAS/LMS software
• Ipeng app
• The WiFi router (Sky fibre/on standard tel line / 76mb)

It’s got to the point where I’m having to consider replacing all my kit as it’s becoming unusable now. But if it’s fixable I would prefer to eek it out a bit longer.

Details:
NAS: Netgear ready NAS running LMS 7.8.0 Perl version 5.8.8 sparc linux
Squeezelite 3.7.7.1

SQB Touch: v7.8.0 (I think!)

IPeng: 9.7.4

Many thanks if anyone can assist here.
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