How to have different 802.11 Mode on 2.4Ghz and 5Ghz - (EX3301-T0)

I just recently set up my new Zyxel EX3301-T0. My phone an different computers had no problem connecting after setting up the router, but an older Windows PC couldn't even find the SSID in the list (neither the primary nor the guest). After some troubleshooting I found that if I change the 802.11 Mode from "802.11b/g/n/ax Mixed" to "802.11b/g/n Mixed" the network appeared in the list.

My question is if there is some way to have "802.11b/g/n/ax Mixed" on the 5Ghz and "802.11b/g/n Mixed" on 2.4GHz. I have tried to look through all the settings and the user manual but I cant find anything. There does seem to be able to do so on other Zyxel products (se the following answer)

so that gives me hope that there is a way. Would be a bummer to either not the able to use the older PC or not be able to use the higher speeds that comes with 802.11ax.

Thanks in advance!