Advice needed for rural ADSL / 4G Combo

[gargoyle123]

Like many people I know, I am stuck with no real prospects of fibre in the next couple of years, so I’m looking to implement a hybrid solution.
I currently have 2Mb ADSL unlimited data and 25-35Mb 4G currently limited to 32Gb per month – I might be able to get it up to 64Mb.

32Gb is not going to go very far – but I would hope with the right hardware / software configuration we can use this to at least provide a responsive internet for general browsing and email using gargoyle quotas to stay within limits.
I am a relative newbie to this and would like to understand a cost effective away of achieving this.
Specifically – ensuring
1) all multimedia is routed through ADSL (easy for Amazon Firestick, Freeview and Chromecast) – easy. Less familiar with users using youtube / music streaming.
2) All software updates routed through ADSL – sure this is possible – just need some pointers
3) Remaining demands managed by ip/user/ monthly quota – if there could be a warning when they got to 80% would be nice rather than cutting them off. This is where I would assume gargoyle could do well.
4) My son does some gaming – his view is “not that much”, I suspect it’s more than his allocation of mobile data will ever cover. If it were possible to allow him so much towards of this per month on mobile and then revert to ADSL when hit capacity that would be a plus.
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Any other suggestions people have on keeping mobile data demands down.

Routers I have are all getting a bit old – nothing that currently supports gargoyle. For 4G I have a Huawei B593 LTE router with an external aerial which is needed to get a signal. This is currently not shared as I have no means of managing quotas.
This is to serve a family household – we also share a wireless network printer. Mix of hardware mostly running windows 10 with a common mix of mobile devices.
I would like to try and do this on a budget. One suggestion was a Draytek 2860LN but at circa £400 I was hoping to try and do it for a lot less if viable. Don’t mind looking at second-hand kit.
I’m guessing I may need a dual WAN / multi WAN with Ethernet links my ADSL router and 4G router together. Just to keep things challenging - The house has lots of solid brick walls so I might need a decent wireless router – cabling is not straight forward – but I may need to at least link two routers. I have tried powerline extenders before - not very successfully. Obviously need a router in the mix that manages the data quota.

All pointers gratefully received – I don’t mind doing more reading – but no router specialist – not yet by a long way.

[ericwong]

Gargoyle does NOT support dual WAN, only fail-over is possible.

You will need to look for other solutions if you want to manage both ADSL and 4G usage independently in dual WAN configuration.

My only suggestion is for you to have your Gargoyle router serving your 4G connection, so you can manage its data consumption and manually change your AP to ADSL/4G when you need it.