i assume it should be added to vht or ht capab you should check how airtime fairness should be enabled from hostapd
did you check Controlling airtime fairness
also i can see this
https://patchwork.ozlabs.org/project/hostap/patch/20190215181129.21216-1-toke@toke.dk/
+#ifdef CONFIG_AIRTIME_POLICY
+ } else if (os_strcmp(buf, "airtime_mode") == 0) {
+ conf->airtime_mode = atoi(pos);
+ } else if (os_strcmp(buf, "airtime_update_interval") == 0) {
+ conf->airtime_update_interval = atoi(pos);
+ } else if (os_strcmp(buf, "airtime_bss_weight") == 0) {
+ bss->airtime_weight = atoi(pos);
+ } else if (os_strcmp(buf, "airtime_bss_limit") == 0) {
+ bss->airtime_limit = atoi(pos);
+ } else if (os_strcmp(buf, "airtime_sta_weight") == 0) {
+ if (add_airtime_weight(bss, pos) < 0) {
+ wpa_printf(MSG_DEBUG, "Line %d: Invalid airtime weight '%s'",
+ line, pos);
+ return 1;
+ }
+#endif /* CONFIG_AIRTIME_POLICY */
and
+##### Airtime policy configuration ###########################################
+
+# Set the airtime policy operating mode:
+# 0 = disabled (default)
+# 1 = static config
+# 2 = per-BSS dynamic config
+# 3 = per-BSS limit mode
+#airtime_mode=0
+
+# Interval (in milliseconds) to poll the kernel for updated station activity in
+# dynamic and limit modes
+#airtime_update_interval=200
+
+# Static configuration of station weights (when airtime_mode=1). Kernel default
+# weight is 256; set higher for larger airtime share, lower for smaller share.
+# Each entry is a MAC address followed by a weight.
+#airtime_sta_weight=02:01:02:03:04:05 256
+#airtime_sta_weight=02:01:02:03:04:06 512
+
+# Per-BSS airtime weight. In multi-bss mode, set for each BSS and hostapd will
+# configure station weights to enforce the correct ratio between BSS weights
+# depending on the number of active stations. The *ratios* between different
+# BSSes is what's important, not the absolute numbers.
+# Must be set for all BSSes if airtime_mode=2 or 3, has no effect otherwise.
+#airtime_bss_weight=1
+
+# Whether the current BSS should be limited (when airtime_mode=3).
+#
+# If set, the BSS weight ratio will be applied in the case where the current BSS
+# would exceed the share defined by the BSS weight ratio. E.g., if two BSSes are
+# set to the same weights, and one is set to limited, the limited BSS will get
+# no more than half the available airtime, but if the non-limited BSS has more
+# stations active, that *will* be allowed to exceed its half of the available
+# airtime.
+#airtime_bss_limit=1
think you should tweak the hostpad.sh to add these extra feature (hardcode them to quickly test and check if the value appear in the supported values)