I have a TL-WR902AC travel router.  Great piece of gear -- but I may be asking too much.   My cell is a dated Pixel 5 (my pretty Pixel 8 went for a deep water swim....).  I'm using this on a boat that gets occasional use (several weeks at various times of the year, but heavy use when actually used.  I do NOT want a dedicated, full time, cell-connected AP (a year subscription for 10-20 days of use is not my idea of a good deal).

Here's my goal:

*  Set up router

*  Permanently connect by WiFi several IoT devices (battery monitor,  instrument monitor, etc) as well as a connected Thumb Drive (that works great for my smart TV!).

*  I also have a printer on the network, and this could be used by connected laptops and cells.

*  Connection OUT to the internet would be nice, but not required.

*  I want my cell to connect to the router, and then to all those things.  I also want my cell to have internet access (like always!).

Here's my challenge:

*  When I connect to the router, my cell will "see" all the network goodness -- but not the internet!

What I've done:

*  I connect to the router with basic settings.  No dice.

*  I connect the router to my phone AP (but don't connect the phone to the router), and any device on the network (my laptop, for instance) has internet (so I know that LAN-phone-internet works)

*  I have tried to set a DNS (8.8.8.8 and 8.8.4.4), no help.

*  If I connect the router to my phone AP AND I connect the phone to the router, my phone still has no internet -- and it breaks the laptop acces to the internet.

*  I have turned on "Switch to mobile data when WiFi has no internet."  When I do that, I can connect to the internet -- but can't open the LAN (192.168.0.1 times out).  Presumably because it has no internet, so it's "paused."

I realize the "circular data path" of connecting to the router, which connects to my cell, which connects to the internet is probably a crazy route, but I don't know why it doesn't work (and why it breaks the hotspot completely).  I really don't need the router to connect to the internet (but it would be nice!).

Long story short -- how can my cell retain normal cell data, while also reaching local IP addreses on the travel router?  Bonus points if the LAN has internet.