Having OpenWrt router in between a tethered smartphone & a desktop

Can i connect an openwrt router between a tethered smartphone
which provides access to the internet - on one side
and a desktop on the other side - to be used for browsing etc ...?
tethered smartphone ---> openwrt router ---> desktop

Could this arrangement provide a significant contribution to
safeguarding my online privacy and security ?

What hardware device / architecture could improve web browsing
security & anonymity via a tethered smartphone ?

I'd appreciate any informed feedback

I imagine the easiest solution would be to make a WWAN on your router and join your mobile hotspot--that should be easier than tethering.

I'm using USB tethering exclusively

Yes.
https://openwrt.org/docs/guide-user/network/wan/smartphone.usb.tethering

This is a common use case, and you can do any firewalling or other security that would be done with other types of Internet connections.

Yes, it works well. For travel I tether my smartphone (running a VPN) to a portable router running OpenWRT with the app EasyTether. This process works well for me plus I don't get any carrier throttling whatsoever. The VPN on the phone is just for added security.

If your looking for lower cost than typical smartphone data plans check out this reddit link:

https://www.reddit.com/r/NoContract/comments/cd5y9f/att_ipadmobile_hotspot_megathread/?utm_source=share&utm_medium=web2x

If you need more info just PM me.

My router (Netgear DM200) has one VDSL port and one LAN port.
There is No USB port
Is there any way to connect this router to a smartphone - maybe some sort
of an adapter / splitter mounted on the LAN port ?