for that reason @jow implemented earlier with non-DSA the default VLANs, so that all default switch configs included a numbered VLAN for lan and wan, like eth0.1 and eth1.2. That decreased the soft-bricks tremendously.
https://github.com/openwrt/openwrt/commit/73d923ed6baabe3f8844f13216c50a6383a79a46
Right now with DSA, we are not generating any explicit switch config at all, so this gets ignored, I think.
(With R7800 I noticed a fixed connection drop immediately when I tried to enable "VLAN filtering". Wlan naturally worked. But there was no reboot loop.)