Blocking wifi remotely for my son

Hi, what for me is a knotty little list of options but hopefully very clear to people here. If easier to call me, or you know someone I can get in touch with, please let me know. I am wanting to do three things:

Enhance my son's wifi speed on his gaming PC

Be able to turn off his PC and iphone Wifi whenever I want, and

Do the above the most cost effectively

I am on Spark with their supplied router, Huawei HG659b. We have just bought James a high-speced gaming PC and PB Tech also got us to buy the TP-Link AV600 Powerline (TL-WPA4220 KIT) to boost his wi-fi. This is plugged into his PC.

James is at home studying for some very big exams and during his breaks his preferred option is to get onto his PC and play Fortnite or his iphone re Youtube, social media etc. However, 10 minutes break can turn into 20 can turn into an hour or so. So I want a way that I can be at work and turn his phone and PC wifi on and off whenever I want, ideally by way of an app. So not a case of preset times, eg. allowing him access between 1pm and 2pm each day, its being able to turn him on and off at otherwise random times. He would text me when he wants to go on, I'd turn him on, and then turn him off at an agreed time.

Searching the net, couldn't find an App that is compatible with the Huawei HG659b (but you may know of one?). I did download the WiFi Blocker app, and it can read my router in terms that it can show me the devices connected. I have turned off one access for one of these but the device can still access wifi. So, it appears it doesnt work. Their site shows they support a range of Huawei routers, including the HG659 but not the H659b, and the app is reading my router as Hg6NN (which it isn't and isn't on their list anyway - so confused). Their support says they can add this router to the app, but this can take a few weeks and involves a lot of legwork from me (by which time James' exams over).

Re remote and random blocking, a friend has suggested Google Wifi. While they do sell it, Noel Leeming suggested that the Netgear Orbi AC2200 2 pack (RBK-20-100AUS) would be a better option. Google WiFi uses its own app, Orbi uses Circle with Disney app.

Questions and options:

Existing setup + App - does anyone know of an app I can use with the Huawei HG659b?

Google Wifi - this plugs into the router, and I can set up a mesh wifi if buy another 1 or 2 (depending on coverage area). If I just bought the one - would we be able to get rid of the TP-Link AV600 Powerline and not affect James' PC's gaming response? His ping on Fortnite with the TP-Link is 25 - 30, without it is higher. I could buy it and test to see if can get away with one. If it wasn't good, could buy two, with the 2nd beside his PC and see what effect that had

Could James just unplug the Google WiFi whenever he wants and just access existing router? And, if so, would I be able to get notification or see later that he has done this?

Orbi - this would replace existing router so no 'unplug Google Wifi' issue (if that is an issue). Would he get same speed if 2nd Orbi beside his PC and no TP-Link? (ie. would return TP-Link for a refund so as to offset overall cost).

I see there are other Orbi's but more expensive - Noel Leeming think could get away with the RBK-20 (but they are not tech specalists)

Any other thoughts - better routers? (bearing in mind my goals of app access, James PC speed and cost) - or software loaded on his PC and phone (bearing in mind, would he able to get around it?)

thanks, Peter