kali rpi4 problem hotspot wifi speed

hi. guys, i have a rpi4 with last version of kali, im using a usb wifi awus1900 (rtl8814au)
i getting internet with rtl usb adaptor on my rpi , when i do a debit test directly on the rpi, im getting around 100mb.

i created a hotspot wifi 5ghz with the wifi of the raspberry , and when i connect on one of my device to this hotspot, and do a speed test, i barely got 10 to 20mb.
i tried to search everywhere a solution but couldn't find anything
someone can help me please ?