chunkeey's forward port to v4.19 is working pretty nicely on ipq8065/ nbg6817 for me, but additional DTS changes will be needed to get the new mainline USB drivers working (I personally don't use USB on my router); see R7500v2 kernel 4.19 test for details.
If SQM is desired, it shouldn't take interested parties that long to get ipq806x bumped to v4.19, probably a better solution than short term package (re-)introductions.