It's not supported https://openwrt.org/toh/start?dataflt[Brand*~]=Zte and very unlikely to ever get supported.
Moreover, most of xDSL all-in-one devices that are supported don't have support for the modem function due to driver unavailability.
My best advic3 of this is your current modem, and you really want OpenWrt: put your ZTE device in bridge mode if you can (where it just works a modem) and get yourself a router/AP that supports OpenWrt.
If budget is little, then you better get a used mid-range device than a cheap new device that will probably have limited storage or RAM.
If you mention your requirements, Internet sales and budget, people will be happy to suggest some alternatives.
You can also have a quick look at the table of hardware