The problem is the WAN smoothing sends packets down both links. You are seeing that your twitch stream is too much for your DSL uplink.
What you probably want to do is create a second tunnel for this traffic, and just use bonding with or without FEC and then use some outbound policy rules to send the traffic to your FusionHub via the second tunnel.
I use the following settings:
SF Tunnel to Vultr
#1 (default) Wan smoothing + FEC (both medium) Both WAN.
#2 No smoothing+ FEC low (or off) for max data transfer Both Wan.
Outbound Policy:
Uplink dependent traffic (by IP or Domain) → SpeedFusion Tunnel #2
Critical applications (Zoom. VPN, work etc) → SpeedFusion Tunnel #1
Default Priority Starlink #1, AT&T #2.
That allows all streaming services to only use Starlink (Netfilx, Amazon etc don’t like CoLo IP space) , Critical traffic has full redundancy, and the bandwidth maxing traffic uses what it can.