Well, I may have spoke too soon.
It seems wifi is unstable and requires removing and readding the kernel modules brcmutil & brcmfmac when wifi stops responding.
DMESG errors
ieee80211 phy0: brcmf_cfg80211_get_station: GET STA INFO failed, -110
brcmf_proto_bcdc_query_dcmd: brcmf_proto_bcdc_msg failed w/status -110
what get's me up again without rebooting
sudo rmmod brcmutil
sudo rmmod brcmfmac
sudo insmod /lib/modules/5.3.0-rc4-rockchip64/kernel/drivers/net/wireless/broadcom/brcm80211/brcmutil/brcmutil.ko
sudo insmod /lib/modules/5.3.0-rc4-rockchip64/kernel/drivers/net/wireless/broadcom/brcm80211/brcmfmac/brcmfmac.ko