Iptables limit vs traffic shaping

Hi everyone.

I was wondering how to stimulate my child to have more social life, but without limiting their Internet possibilities. So, I was checking and reading about QoS, SQM, Traffic shaping and all that stuff. However, all that seems overkiller for what I need, and also, my router is not the most flexible to install new packages (TP-Link WRT741N), so I checked if there were some easier option, that won't involve to install any other package. So, I attempted to use iptables limit and limit-burst, and so far, it's working very well.

I did something like this to limit the bandwidth:

iptables -A forwarding_rule -i eth1 -d -m limit --limit 13/sec --limit-burst 13 -j ACCEPT
iptables -A forwarding_rule -i eth1 -d -j DROP

Obvoiusly, the DHCP has that IP reserved for his cell phone.

So far so good, the internet works, but it's very slow, online gaming is pretty impossible, and youtube videos stop playing permanently, even on 144p. However, text chat and most of text websites loads OK.

My question is: most of suggestions in forums about limiting bandwidth for a device refers to SQM. Is my approach worse? I know I don't have much of the flexibility that SQM gives, but I don't think I need anything else. Could I have any issue with this scenario? Is this too much stress for the device?

I don't think you'll get what you want with sqm. It tries to give a fair amount of bandwidth to every user and at the same time avoid bufferbloat. If you want to do micromanagement of the bandwidth give qos or luci-app-nft-qos a try.