You linked to two tutorials and it is difficult to follow what you have done. But there are some general issues that are worth mentioning.
By far the most problems reported here on this site is about static ip addresses and there are tons of answers. The reason is that static ip addresses are a manual intervention into the network configuration and you have to do then all other settings also by yourself. If you do not have enough knowledge about it then let the DHCP server do the work. It knows it better. Or read a general networking tutorial. So I will not invest to another duplicate answer about fixing static ip addresses.
I will give some information about the bridge because it's independent from ip addresses. It does not use ip addresses, only mac addresses. This is also the reason why you cannot connect to the bridge, but only to the RasPi the bridge is working on. You can only connect devices to the access point (or to the ethernet/usb interface). If connected to the AP, its devices seem to be on the same subnet as the ethernet/usb connected internet router: wifi interface and ethernet/usb interface are bridged. You can give the RasPi an ip address but that is not the bridge. It is the RasPi, behaving like any other device on the bridged network. This is mostly important because the bridge itself is completely transparent and cannot be seen by other devices on the network and you may have to manage the bridge on the RasPi. But in general the RasPi do not need an ip address for a working bridge.
So the first step should be to make the bridge working without having focus on static ip addresses. If you can ping the ethernet/usb interface from any device connected to the access point, then this part is done. All ip addresses, in particular the ethernet/usb interface, must be on the same subnet.
If this is working then you can try to set static ip addresses as you would do on an unbridged network. It doesn't hurt the bridge. Just query for static ip address.
With yet another setup that do not need additional helper programs like
dnsmasq I can help you: Setting up a Raspberry Pi as an access point - the easy way. Just follow section ♦ Setting up an access point with a bridge if you like.