Broadband Internet & ISP Recommendations?

We're moving house in the next two weeks, and were in a contract for another 13 months with Plusnet. The service available from Plusnet in our new place is very, very poor.

They said they needed two weeks notice and £190 in early termination fees to get away. I was all pleased with myself because I got politely grumpy with them and they waived the termination fees, and cancelled our contract.

Anticipating the required two week notice period, I absent-mindedly started Googling alternative options at our new place (we don't have a move date yet, but it will be less than two weeks) ... then our internet connection disappeared 20 minutes later.

The story was for fun. But the question I had was: Does anyone have any cheap way to patch a 5G connection into a router that doesn't support USB modems? There seems to be plenty of options, all of which cost about £190.

So far I've thought of:

• Old Android phone, USB-OTG to Ethernet cable. Problem: Can't charge the phone and provide internet.
  
• 5G SIM-based router/modem. Problem: Expensive. Used for £150-190 or so. But maybe I could re-sell for the same in a few weeks.
  
• New router that does support USB modems, then use the old Android phone. Problem. Expensive, but maybe I need a new router anyway.
  
  

Any good ideas?