More trains do call at Shotton now compared with when I was a 'boy', but I've always been surprised at the low footfall when you consider how populated that area is, and how much industry and cross-border traffic there is. I'd always assumed the local bus services were more useful, but that's not my area of Wales so I defer to others.
I don't go back that often, but the opinions of my relatives in north Wales about the service offered on that line are generally very poor and unloved. They have the perception that a lot of the service has been robbed of usefulness by diverting many trains through Wrexham and Shrewsbury to serve the north-south Wales market, rather than the arguably more useful trains towards Crewe and Manchester. Overcrowding issues caused by short 'boat' trains also hampers the perception of the service.
Pre-Covid, the core Shotton service was hourly all stops to Manchester Airport and Llandudno, with occasional stops to other destinations in the peak, mostly on decent 175/158 trains.
The Crewe/Holyhead trains didn't normally stop, but these are the ones which were diverted to Shrewsbury/Cardiff and the "long way round" to Birmingham.
Trains to/from Chester are indeed very crowded at times, especially when a 2-car turns up which is quite normal.
Arriva buses are quite frequent on the main coast road, roughly 4bph taking half an hour (but dumping you at the new Chester bus station which is 12 mins walk to the railway station).
Many larger places than Shotton only boast an hourly train service (eg Runcorn East), or don't have a direct service to Manchester Airport.
Currently with Covid, almost all through services to Manchester start from Chester, and the 1tph stopper is a Holyhead-Shrewsbury/Birmingham.
Interchanges between the two lines were 19K for 2018/19, for typically 1tph towards Wrexham/Bidston.
Connections are not too bad, particularly westwards, considering the times are not coordinated in any way.
The alternative for Liverpool is to go on to Chester where you have 4tph Merseyrail and 1tph TfW.
If ever the class 230s show up on the Wrexham-Bidston line, a 2tph service would improve things a lot.