Merge queries for alerts

Hi I have two queries that gather the hard disk usage for windows and linux instances. Previously I had an alert in that graph that would trigger if one of those went above a threshold.
I can’t get this to work with the new system. Do I have to split this up in windows and linux?
The queries:

100 - ((windows_logical_disk_free_bytes{job=~"node-exporter", volume !~"HarddiskVolume.*"}  *100 )/ windows_logical_disk_size_bytes{job=~"node-exporter", volume !~"HarddiskVolume.*"})

100 - ((node_filesystem_avail_bytes{fstype=~"ext.*|xfs",mountpoint !~".*pod.*||/boot"} * 100) / node_filesystem_size_bytes{fstype=~"ext.*|xfs",mountpoint !~".*pod.*||/boot"})

I tried a reduce function for each query to have a single value per mountpoint that is used and then with a math expression.

The reduce functions work but I cannot use it with the math expression. I tried:

$A > 80 // worked

$B > 80 // worked

$A > 80 || $B > 80 // no data

I read that I have to use a resample expression but I can’t get that to work either.

grafana version is 9.0.0