Traffic shaper is massively lowering bandwidth

[lexx.ps2711]

Hello everyone,
I just recently switched from pfSense to OPNSense again and I was really enjoying it until I got some weird issues with the traffic shaper...

To give you a rough overview about my setup I will give you some details...
I am running OPNSense together with Adguard as primary DNS. Adguard uses Unbound as resolver and Unbound forwards requests to quad9 DoT servers. Also I am using the inbuilt IDS listening on my IOT VLAN only. I also configured wireguard and Hybrid NAT, but I don't use it when the issue occurs.
There are also two port forwards on 80 and 443 that forward requests to a server running npm.

The problem I am facing right now is that the traffic shaper cuts off far too much from my bandwidth. I configured it according to this guide https://forum.opnsense.org/index.php?topic=7423.0 with 225 Mbit/s down and 37 Mbit/s up. For the last 5 days this was working just fine and today issues started to occur.
It also seems to only happen when connected via WiFi (AP is a Fritz!Box 4040 running OpenWRT in dumb AP mode), since speeds were totally fine when using cable. I couldn't test on my main machine, but same was happening when sitting next to the AP with a laptop.

This way I know that it is unlikely to be a hardware issue now. Afterwards the first idea was to disable the traffic shaper and things started to change. Speeds go up to max again and everything seems to be fine. When I enabled the shaper again and reconnected my WiFi it's broken again.

The issue seems to be the traffic shaper then. To verify it's nothing else I am running I also tried disabling IDS with the shaper active and the measured bandwidth was still terribly low. I highly doubt this is an DNS issue since the DNS is not responsible for downloads itself.

To clarify this... Nothing changed before this happened. Everything worked just fine yesterday and today this happened.
For now the only way to fix this is disabling the traffic shaper. I would really like to have it enabled in the future, since bufferbloat can be kinda annoying in online games 

Maybe someone here can tell me if this is a known issue or if there is something I missed. I am by far no network expert, but I think my debugging steps were enough to find the root cause.

EDIT: Added more setup info

[meyergru]

Are you sure that it is not a hidden MTU/MSS issue? You should be sure to have the correct MTU for you whole path over WiFi (maybe on a VLAN cutting off a few bytes?), Traffic Shaper, OpnSense, PPPoE (also cutting off a few bytes).

Just guessing because both the traffic shaper and your WiFi might influence packet resequencing.